Communication of cell configuration parameters of an unlicensed cell

ABSTRACT

A first base station may receive, from a second base station, cell configuration parameters of one or more cells of the second base station. The cell configuration parameters may indicating at least one first information element (IE) indicating a first identifier of a first cell of the one or more cells, at least one second IE indicating that the first cell is an unlicensed cell, and at least one third IE indicating radio frequency channel number of the unlicensed cell. The first base station may send, to the second base station, a handover request message for a wireless device after receiving the cell configuration parameters.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/111,586, filed Dec. 4, 2020, which is a continuation of U.S. patentapplication Ser. No. 16/508,261, filed Jul. 10, 2019, which is acontinuation of U.S. patent application Ser. No. 15/846,721, filed Dec.19, 2017, which claims the benefit of U.S. Provisional Application No.62/436,836, filed Dec. 20, 2016, all of which are hereby incorporated byreference in their entireties.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Examples of several of the various embodiments of the present inventionare described herein with reference to the drawings.

FIG. 1 is a diagram depicting example sets of OFDM subcarriers as per anaspect of an embodiment of the present disclosure.

FIG. 2 is a diagram depicting an example transmission time and receptiontime for two carriers in a carrier group as per an aspect of anembodiment of the present disclosure.

FIG. 3 is a diagram depicting OFDM radio resources as per an aspect ofan embodiment of the present disclosure.

FIG. 4 is a block diagram of a base station and a wireless device as peran aspect of an embodiment of the present disclosure.

FIG. 5A, FIG. 5B, FIG. 5C and FIG. 5D are example diagrams for uplinkand downlink signal transmission as per an aspect of an embodiment ofthe present disclosure.

FIG. 6 is an example diagram for a protocol structure with CA and DC asper an aspect of an embodiment of the present disclosure.

FIG. 7 is an example diagram for a protocol structure with CA and DC asper an aspect of an embodiment of the present disclosure.

FIG. 8 shows example TAG configurations as per an aspect of anembodiment of the present disclosure.

FIG. 9 is an example message flow in a random access process in asecondary TAG as per an aspect of an embodiment of the presentdisclosure.

FIG. 10 is an example message flow diagram as per an aspect of anembodiment of the present disclosure.

FIG. 11 is an example message flow diagram as per an aspect of anembodiment of the present disclosure.

FIG. 12 is an example message flow diagram as per an aspect of anembodiment of the present disclosure.

FIG. 13 is an example message flow diagram as per an aspect of anembodiment of the present disclosure.

FIG. 14 is an example message flow diagram as per an aspect of anembodiment of the present disclosure.

FIG. 15 is a flow diagram of an aspect of an embodiment of the presentdisclosure.

FIG. 16 is a flow diagram of an aspect of an embodiment of the presentdisclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Example embodiments of the present invention enable operation of carrieraggregation. Embodiments of the technology disclosed herein may beemployed in the technical field of multicarrier communication systems.More particularly, the embodiments of the technology disclosed hereinmay relate to signal timing in multicarrier communication systems.

The following Acronyms are used throughout the present disclosure:

-   -   ASIC application-specific integrated circuit    -   BPSK binary phase shift keying    -   CA carrier aggregation    -   CSI channel state information    -   CDMA code division multiple access    -   CSS common search space    -   CPLD complex programmable logic devices    -   CC component carrier    -   DL downlink    -   DCI downlink control information    -   DC dual connectivity    -   EPC evolved packet core    -   E-UTRAN evolved-universal terrestrial radio access network    -   FPGA field programmable gate arrays    -   FDD frequency division multiplexing    -   HDL hardware description languages    -   HARQ hybrid automatic repeat request    -   IE information element    -   LTE long term evolution    -   MCG master cell group    -   MeNB master evolved node B    -   MIB master information block    -   MAC media access control    -   MAC media access control    -   MME mobility management entity    -   NAS non-access stratum    -   OFDM orthogonal frequency division multiplexing    -   PDCP packet data convergence protocol    -   PDU packet data unit    -   PHY physical    -   PDCCH physical downlink control channel    -   PHICH physical HARQ indicator channel    -   PUCCH physical uplink control channel    -   PUSCH physical uplink shared channel    -   PCell primary cell    -   PCell primary cell    -   PCC primary component carrier    -   PSCell primary secondary cell    -   pTAG primary timing advance group    -   QAM quadrature amplitude modulation    -   QPSK quadrature phase shift keying    -   RBG Resource Block Groups    -   RLC radio link control    -   RRC radio resource control    -   RA random access    -   RB resource blocks    -   SCC secondary component carrier    -   SCell secondary cell    -   Scell secondary cells    -   SCG secondary cell group    -   SeNB secondary evolved node B    -   sTAGs secondary timing advance group    -   SDU service data unit    -   S-GW serving gateway    -   SRB signaling radio bearer    -   SC-OFDM single carrier-OFDM    -   SFN system frame number    -   SIB system information block    -   TAI tracking area identifier    -   TAT time alignment timer    -   TDD time division duplexing    -   TDMA time division multiple access    -   TA timing advance    -   TAG timing advance group    -   TB transport block    -   UL uplink    -   UE user equipment    -   VHDL VHSIC hardware description language

Example embodiments of the invention may be implemented using variousphysical layer modulation and transmission mechanisms. Exampletransmission mechanisms may include, but are not limited to: CDMA, OFDM,TDMA, Wavelet technologies, and/or the like. Hybrid transmissionmechanisms such as TDMA/CDMA, and OFDM/CDMA may also be employed.Various modulation schemes may be applied for signal transmission in thephysical layer. Examples of modulation schemes include, but are notlimited to: phase, amplitude, code, a combination of these, and/or thelike. An example radio transmission method may implement QAM using BPSK,QPSK, 16-QAM, 64-QAM, 256-QAM, and/or the like. Physical radiotransmission may be enhanced by dynamically or semi-dynamically changingthe modulation and coding scheme depending on transmission requirementsand radio conditions.

FIG. 1 is a diagram depicting example sets of OFDM subcarriers as per anaspect of an embodiment of the present invention. As illustrated in thisexample, arrow(s) in the diagram may depict a subcarrier in amulticarrier OFDM system. The OFDM system may use technology such asOFDM technology, DFTS-OFDM, SC-OFDM technology, or the like. Forexample, arrow 101 shows a subcarrier transmitting information symbols.FIG. 1 is for illustration purposes, and a typical multicarrier OFDMsystem may include more subcarriers in a carrier. For example, thenumber of subcarriers in a carrier may be in the range of 10 to 10,000subcarriers. FIG. 1 shows two guard bands 106 and 107 in a transmissionband. As illustrated in FIG. 1 , guard band 106 is between subcarriers103 and subcarriers 104. The example set of subcarriers A 102 includessubcarriers 103 and subcarriers 104. FIG. 1 also illustrates an exampleset of subcarriers B 105. As illustrated, there is no guard band betweenany two subcarriers in the example set of subcarriers B 105. Carriers ina multicarrier OFDM communication system may be contiguous carriers,non-contiguous carriers, or a combination of both contiguous andnon-contiguous carriers.

FIG. 2 is a diagram depicting an example transmission time and receptiontime for two carriers as per an aspect of an embodiment of the presentinvention. A multicarrier OFDM communication system may include one ormore carriers, for example, ranging from 1 to 10 carriers. Carrier A 204and carrier B 205 may have the same or different timing structures.Although FIG. 2 shows two synchronized carriers, carrier A 204 andcarrier B 205 may or may not be synchronized with each other. Differentradio frame structures may be supported for FDD and TDD duplexmechanisms. FIG. 2 shows an example FDD frame timing. Downlink anduplink transmissions may be organized into radio frames 201. In thisexample, radio frame duration is 10 msec. Other frame durations, forexample, in the range of 1 to 100 msec may also be supported. In thisexample, each 10 ms radio frame 201 may be divided into ten equallysized subframes 202. Other subframe durations such as including 0.5msec, 1 msec, 2 msec, and 5 msec may also be supported. Subframe(s) mayconsist of two or more slots (e.g. slots 206 and 207). For the exampleof FDD, 10 subframes may be available for downlink transmission and 10subframes may be available for uplink transmissions in each 10 msinterval. Uplink and downlink transmissions may be separated in thefrequency domain. Slot(s) may include a plurality of OFDM symbols 203.The number of OFDM symbols 203 in a slot 206 may depend on the cyclicprefix length and subcarrier spacing.

FIG. 3 is a diagram depicting OFDM radio resources as per an aspect ofan embodiment of the present invention. The resource grid structure intime 304 and frequency 305 is illustrated in FIG. 3 . The quantity ofdownlink subcarriers or RBs (in this example 6 to 100 RBs) may depend,at least in part, on the downlink transmission bandwidth 306 configuredin the cell. The smallest radio resource unit may be called a resourceelement (e.g. 301). Resource elements may be grouped into resourceblocks (e.g. 302). Resource blocks may be grouped into larger radioresources called Resource Block Groups (RBG) (e.g. 303). The transmittedsignal in slot 206 may be described by one or several resource grids ofa plurality of subcarriers and a plurality of OFDM symbols. Resourceblocks may be used to describe the mapping of certain physical channelsto resource elements. Other pre-defined groupings of physical resourceelements may be implemented in the system depending on the radiotechnology. For example, 24 subcarriers may be grouped as a radio blockfor a duration of 5 msec. In an illustrative example, a resource blockmay correspond to one slot in the time domain and 180 kHz in thefrequency domain (for 15 KHz subcarrier bandwidth and 12 subcarriers).

FIG. 5A, FIG. 5B, FIG. 5C and FIG. 5D are example diagrams for uplinkand downlink signal transmission as per an aspect of an embodiment ofthe present invention. FIG. 5A shows an example uplink physical channel.The baseband signal representing the physical uplink shared channel mayperform the following processes. These functions are illustrated asexamples and it is anticipated that other mechanisms may be implementedin various embodiments. The functions may comprise scrambling,modulation of scrambled bits to generate complex-valued symbols, mappingof the complex-valued modulation symbols onto one or severaltransmission layers, transform precoding to generate complex-valuedsymbols, precoding of the complex-valued symbols, mapping of precodedcomplex-valued symbols to resource elements, generation ofcomplex-valued time-domain DFTS-OFDM/SC-FDMA signal for each antennaport, and/or the like.

Example modulation and up-conversion to the carrier frequency of thecomplex-valued DFTS-OFDM/SC-FDMA baseband signal for each antenna portand/or the complex-valued PRACH baseband signal is shown in FIG. 5B.Filtering may be employed prior to transmission.

An example structure for Downlink Transmissions is shown in FIG. 5C. Thebaseband signal representing a downlink physical channel may perform thefollowing processes. These functions are illustrated as examples and itis anticipated that other mechanisms may be implemented in variousembodiments. The functions include scrambling of coded bits in each ofthe codewords to be transmitted on a physical channel; modulation ofscrambled bits to generate complex-valued modulation symbols; mapping ofthe complex-valued modulation symbols onto one or several transmissionlayers; precoding of the complex-valued modulation symbols on each layerfor transmission on the antenna ports; mapping of complex-valuedmodulation symbols for each antenna port to resource elements;generation of complex-valued time-domain OFDM signal for each antennaport, and/or the like.

Example modulation and up-conversion to the carrier frequency of thecomplex-valued OFDM baseband signal for each antenna port is shown inFIG. 5D. Filtering may be employed prior to transmission.

FIG. 4 is an example block diagram of a base station 401 and a wirelessdevice 406, as per an aspect of an embodiment of the present invention.A communication network 400 may include at least one base station 401and at least one wireless device 406. The base station 401 may includeat least one communication interface 402, at least one processor 403,and at least one set of program code instructions 405 stored innon-transitory memory 404 and executable by the at least one processor403. The wireless device 406 may include at least one communicationinterface 407, at least one processor 408, and at least one set ofprogram code instructions 410 stored in non-transitory memory 409 andexecutable by the at least one processor 408. Communication interface402 in base station 401 may be configured to engage in communicationwith communication interface 407 in wireless device 406 via acommunication path that includes at least one wireless link 411.Wireless link 411 may be a bi-directional link. Communication interface407 in wireless device 406 may also be configured to engage in acommunication with communication interface 402 in base station 401. Basestation 401 and wireless device 406 may be configured to send andreceive data over wireless link 411 using multiple frequency carriers.According to some of the various aspects of embodiments, transceiver(s)may be employed. A transceiver is a device that includes both atransmitter and receiver. Transceivers may be employed in devices suchas wireless devices, base stations, relay nodes, and/or the like.Example embodiments for radio technology implemented in communicationinterface 402, 407 and wireless link 411 are illustrated are FIG. 1 ,FIG. 2 , FIG. 3 , FIG. 5 , and associated text.

An interface may be a hardware interface, a firmware interface, asoftware interface, and/or a combination thereof. The hardware interfacemay include connectors, wires, electronic devices such as drivers,amplifiers, and/or the like. A software interface may include codestored in a memory device to implement protocol(s), protocol layers,communication drivers, device drivers, combinations thereof, and/or thelike. A firmware interface may include a combination of embeddedhardware and code stored in and/or in communication with a memory deviceto implement connections, electronic device operations, protocol(s),protocol layers, communication drivers, device drivers, hardwareoperations, combinations thereof, and/or the like.

The term configured may relate to the capacity of a device whether thedevice is in an operational or non-operational state. Configured mayalso refer to specific settings in a device that effect the operationalcharacteristics of the device whether the device is in an operational ornon-operational state. In other words, the hardware, software, firmware,registers, memory values, and/or the like may be “configured” within adevice, whether the device is in an operational or nonoperational state,to provide the device with specific characteristics. Terms such as “acontrol message to cause in a device” may mean that a control messagehas parameters that may be used to configure specific characteristics inthe device, whether the device is in an operational or non-operationalstate.

According to some of the various aspects of embodiments, an LTE networkmay include a multitude of base stations, providing a user planePDCP/RLC/MAC/PHYand control plane (RRC) protocol terminations towardsthe wireless device. The base station(s) may be interconnected withother base station(s) (e.g. employing an X2 interface). The basestations may also be connected employing, for example, an S1 interfaceto an EPC. For example, the base stations may be interconnected to theMME employing the S1-MME interface and to the S-G) employing the S1-Uinterface. The S1 interface may support a many-to-many relation betweenMMEs/Serving Gateways and base stations. A base station may include manysectors for example: 1, 2, 3, 4, or 6 sectors. A base station mayinclude many cells, for example, ranging from 1 to 50 cells or more. Acell may be categorized, for example, as a primary cell or secondarycell. At RRC connection establishment/re-establishment/handover, oneserving cell may provide the NAS (non-access stratum) mobilityinformation (e.g. TAI), and at RRC connection re-establishment/handover,one serving cell may provide the security input. This cell may bereferred to as the Primary Cell (PCell). In the downlink, the carriercorresponding to the PCell may be the Downlink Primary Component Carrier(DL PCC), while in the uplink, it may be the Uplink Primary ComponentCarrier (UL PCC). Depending on wireless device capabilities, SecondaryCells (SCells) may be configured to form together with the PCell a setof serving cells. In the downlink, the carrier corresponding to an SCellmay be a Downlink Secondary Component Carrier (DL SCC), while in theuplink, it may be an Uplink Secondary Component Carrier (UL SCC). AnSCell may or may not have an uplink carrier.

A cell, comprising a downlink carrier and optionally an uplink carrier,may be assigned a physical cell ID and a cell index. A carrier (downlinkor uplink) may belong to only one cell. The cell ID or Cell index mayalso identify the downlink carrier or uplink carrier of the cell(depending on the context it is used). In the specification, cell ID maybe equally referred to a carrier ID, and cell index may be referred tocarrier index. In implementation, the physical cell ID or cell index maybe assigned to a cell. A cell ID may be determined using asynchronization signal transmitted on a downlink carrier. A cell indexmay be determined using RRC messages. For example, when thespecification refers to a first physical cell ID for a first downlinkcarrier, the specification may mean the first physical cell ID is for acell comprising the first downlink carrier. The same concept may applyto, for example, carrier activation. When the specification indicatesthat a first carrier is activated, the specification may equally meanthat the cell comprising the first carrier is activated.

Embodiments may be configured to operate as needed. The disclosedmechanism may be performed when certain criteria are met, for example,in a wireless device, a base station, a radio environment, a network, acombination of the above, and/or the like. Example criteria may bebased, at least in part, on for example, traffic load, initial systemset up, packet sizes, traffic characteristics, a combination of theabove, and/or the like. When the one or more criteria are met, variousexample embodiments may be applied. Therefore, it may be possible toimplement example embodiments that selectively implement disclosedprotocols.

A base station may communicate with a mix of wireless devices. Wirelessdevices may support multiple technologies, and/or multiple releases ofthe same technology. Wireless devices may have some specificcapability(ies) depending on its wireless device category and/orcapability(ies). A base station may comprise multiple sectors. When thisdisclosure refers to a base station communicating with a plurality ofwireless devices, this disclosure may refer to a subset of the totalwireless devices in a coverage area. This disclosure may refer to, forexample, a plurality of wireless devices of a given LTE release with agiven capability and in a given sector of the base station. Theplurality of wireless devices in this disclosure may refer to a selectedplurality of wireless devices, and/or a subset of total wireless devicesin a coverage area which perform according to disclosed methods, and/orthe like. There may be a plurality of wireless devices in a coveragearea that may not comply with the disclosed methods, for example,because those wireless devices perform based on older releases of LTEtechnology.

FIG. 6 and FIG. 7 are example diagrams for protocol structure with CAand DC as per an aspect of an embodiment of the present invention.E-UTRAN may support Dual Connectivity (DC) operation whereby a multipleRX/TX UE in RRC_CONNECTED may be configured to utilize radio resourcesprovided by two schedulers located in two eNBs connected via a non-idealbackhaul over the X2 interface. eNBs involved in DC for a certain UE mayassume two different roles: an eNB may either act as an MeNB or as anSeNB. In DC a UE may be connected to one MeNB and one SeNB. Mechanismsimplemented in DC may be extended to cover more than two eNBs. FIG. 7illustrates one example structure for the UE side MAC entities when aMaster Cell Group (MCG) and a Secondary Cell Group (SCG) are configured,and it may not restrict implementation. Media Broadcast MulticastService (MBMS) reception is not shown in this figure for simplicity.

In DC, the radio protocol architecture that a particular bearer uses maydepend on how the bearer is setup. Three alternatives may exist, an MCGbearer, an SCG bearer and a split bearer as shown in FIG. 6 . RRC may belocated in MeNB and SRBs may be configured as a MCG bearer type and mayuse the radio resources of the MeNB. DC may also be described as havingat least one bearer configured to use radio resources provided by theSeNB. DC may or may not be configured/implemented in example embodimentsof the invention.

In the case of DC, the UE may be configured with two MAC entities: oneMAC entity for MeNB, and one MAC entity for SeNB. In DC, the configuredset of serving cells for a UE may comprise of two subsets: the MasterCell Group (MCG) containing the serving cells of the MeNB, and theSecondary Cell Group (SCG) containing the serving cells of the SeNB. Fora SCG, one or more of the following may be applied: at least one cell inthe SCG has a configured UL CC and one of them, named PSCell (or PCellof SCG, or sometimes called PCell), is configured with PUCCH resources;when the SCG is configured, there may be at least one SCG bearer or oneSplit bearer; upon detection of a physical layer problem or a randomaccess problem on a PSCell, or the maximum number of RLC retransmissionshas been reached associated with the SCG, or upon detection of an accessproblem on a PSCell during a SCG addition or a SCG change: a RRCconnection re-establishment procedure may not be triggered, ULtransmissions towards cells of the SCG are stopped, a MeNB may beinformed by the UE of a SCG failure type, for split bearer, the DL datatransfer over the MeNB is maintained; the RLC AM bearer may beconfigured for the split bearer; like PCell, PSCell may not bede-activated; PSCell may be changed with a SCG change (e.g. withsecurity key change and a RACH procedure); and/or neither a directbearer type change between a Split bearer and a SCG bearer norsimultaneous configuration of a SCG and a Split bearer are supported.

With respect to the interaction between a MeNB and a SeNB, one or moreof the following principles may be applied: the MeNB may maintain theRRM measurement configuration of the UE and may, (e.g., based onreceived measurement reports or traffic conditions or bearer types),decide to ask a SeNB to provide additional resources (serving cells) fora UE; upon receiving a request from the MeNB, a SeNB may create acontainer that may result in the configuration of additional servingcells for the UE (or decide that it has no resource available to do so);for UE capability coordination, the MeNB may provide (part of) the ASconfiguration and the UE capabilities to the SeNB; the MeNB and the SeNBmay exchange information about a UE configuration by employing of RRCcontainers (inter-node messages) carried in X2 messages; the SeNB mayinitiate a reconfiguration of its existing serving cells (e.g., PUCCHtowards the SeNB); the SeNB may decide which cell is the PSCell withinthe SCG; the MeNB may not change the content of the RRC configurationprovided by the SeNB; in the case of a SCG addition and a SCG SCelladdition, the MeNB may provide the latest measurement results for theSCG cell(s); both a MeNB and a SeNB may know the SFN and subframe offsetof each other by OAM, (e.g., for the purpose of DRX alignment andidentification of a measurement gap). In an example, when adding a newSCG SCell, dedicated RRC signaling may be used for sending requiredsystem information of the cell as for CA, except for the SFN acquiredfrom a MIB of the PSCell of a SCG.

In an example, serving cells may be grouped in a TA group (TAG). Servingcells in one TAG may use the same timing reference. For a given TAG,user equipment (UE) may use at least one downlink carrier as a timingreference. For a given TAG, a UE may synchronize uplink subframe andframe transmission timing of uplink carriers belonging to the same TAG.In an example, serving cells having an uplink to which the same TAapplies may correspond to serving cells hosted by the same receiver. AUE supporting multiple TAs may support two or more TA groups. One TAgroup may contain the PCell and may be called a primary TAG (pTAG). In amultiple TAG configuration, at least one TA group may not contain thePCell and may be called a secondary TAG (sTAG). In an example, carrierswithin the same TA group may use the same TA value and/or the sametiming reference. When DC is configured, cells belonging to a cell group(MCG or SCG) may be grouped into multiple TAGs including a pTAG and oneor more sTAGs.

FIG. 8 shows example TAG configurations as per an aspect of anembodiment of the present invention. In Example 1, pTAG comprises PCell,and an sTAG comprises SCell1. In Example 2, a pTAG comprises a PCell andSCell1, and an sTAG comprises SCell2 and SCell3. In Example 3, pTAGcomprises PCell and SCell1, and an sTAG1 includes SCell2 and SCell3, andsTAG2 comprises SCell4. Up to four TAGs may be supported in a cell group(MCG or SCG) and other example TAG configurations may also be provided.In various examples in this disclosure, example mechanisms are describedfor a pTAG and an sTAG. Some of the example mechanisms may be applied toconfigurations with multiple sTAGs.

In an example, an eNB may initiate an RA procedure via a PDCCH order foran activated SCell. This PDCCH order may be sent on a scheduling cell ofthis SCell. When cross carrier scheduling is configured for a cell, thescheduling cell may be different than the cell that is employed forpreamble transmission, and the PDCCH order may include an SCell index.At least a non-contention based RA procedure may be supported forSCell(s) assigned to sTAG(s).

FIG. 9 is an example message flow in a random access process in asecondary TAG as per an aspect of an embodiment of the presentinvention. An eNB transmits an activation command 600 to activate anSCell. A preamble 602 (Msg1) may be sent by a UE in response to a PDCCHorder 601 on an SCell belonging to an sTAG. In an example embodiment,preamble transmission for SCells may be controlled by the network usingPDCCH format 1A. Msg2 message 603 (RAR: random access response) inresponse to the preamble transmission on the SCell may be addressed toRA-RNTI in a PCell common search space (CSS). Uplink packets 604 may betransmitted on the SCell in which the preamble was transmitted.

According to some of the various aspects of embodiments, initial timingalignment may be achieved through a random access procedure. This mayinvolve a UE transmitting a random access preamble and an eNB respondingwith an initial TA command NTA (amount of timing advance) within arandom access response window. The start of the random access preamblemay be aligned with the start of a corresponding uplink subframe at theUE assuming NTA=0. The eNB may estimate the uplink timing from therandom access preamble transmitted by the UE. The TA command may bederived by the eNB based on the estimation of the difference between thedesired UL timing and the actual UL timing. The UE may determine theinitial uplink transmission timing relative to the correspondingdownlink of the sTAG on which the preamble is transmitted.

The mapping of a serving cell to a TAG may be configured by a servingeNB with RRC signaling. The mechanism for TAG configuration andreconfiguration may be based on RRC signaling. According to some of thevarious aspects of embodiments, when an eNB performs an SCell additionconfiguration, the related TAG configuration may be configured for theSCell. In an example embodiment, an eNB may modify the TAG configurationof an SCell by removing (releasing) the SCell and adding(configuring) anew SCell (with the same physical cell ID and frequency) with an updatedTAG ID. The new SCell with the updated TAG ID may initially be inactivesubsequent to being assigned the updated TAG ID. The eNB may activatethe updated new SCell and start scheduling packets on the activatedSCell. In an example implementation, it may not be possible to changethe TAG associated with an SCell, but rather, the SCell may need to beremoved and a new SCell may need to be added with another TAG. Forexample, if there is a need to move an SCell from an sTAG to a pTAG, atleast one RRC message, for example, at least one RRC reconfigurationmessage, may be send to the UE to reconfigure TAG configurations byreleasing the SCell and then configuring the SCell as a part of the pTAG(when an SCell is added/configured without a TAG index, the SCell may beexplicitly assigned to the pTAG). The PCell may not change its TA groupand may be a member of the pTAG.

The purpose of an RRC connection reconfiguration procedure may be tomodify an RRC connection, (e.g. to establish, modify and/or release RBs,to perform handover, to setup, modify, and/or release measurements, toadd, modify, and/or release SCells). If the received RRC ConnectionReconfiguration message includes the sCellToReleaseList, the UE mayperform an SCell release. If the received RRC Connection Reconfigurationmessage includes the sCellToAddModList, the UE may perform SCelladditions or modification.

In LTE Release-10 and Release-11 CA, a PUCCH is only transmitted on thePCell (PSCell) to an eNB. In LTE-Release 12 and earlier, a UE maytransmit PUCCH information on one cell (PCell or PSCell) to a given eNB.

As the number of CA capable UEs and also the number of aggregatedcarriers increase, the number of PUCCHs and also the PUCCH payload sizemay increase. Accommodating the PUCCH transmissions on the PCell maylead to a high PUCCH load on the PCell. A PUCCH on an SCell may beintroduced to offload the PUCCH resource from the PCell. More than onePUCCH may be configured for example, a PUCCH on a PCell and anotherPUCCH on an SCell. In the example embodiments, one, two or more cellsmay be configured with PUCCH resources for transmitting CSI/ACK/NACK toa base station. Cells may be grouped into multiple PUCCH groups, and oneor more cell within a group may be configured with a PUCCH. In anexample configuration, one SCell may belong to one PUCCH group. SCellswith a configured PUCCH transmitted to a base station may be called aPUCCH SCell, and a cell group with a common PUCCH resource transmittedto the same base station may be called a PUCCH group.

In an example embodiment, a MAC entity may have a configurable timertimeAlignmentTimer per TAG. The timeAlignmentTimer may be used tocontrol how long the MAC entity considers the Serving Cells belonging tothe associated TAG to be uplink time aligned. The MAC entity may, when aTiming Advance Command MAC control element is received, apply the TimingAdvance Command for the indicated TAG; start or restart thetimeAlignmentTimer associated with the indicated TAG. The MAC entitymay, when a Timing Advance Command is received in a Random AccessResponse message for a serving cell belonging to a TAG and/or if theRandom Access Preamble was not selected by the MAC entity, apply theTiming Advance Command for this TAG and start or restart thetimeAlignmentTimer associated with this TAG. Otherwise, if thetimeAlignmentTimer associated with this TAG is not running, the TimingAdvance Command for this TAG may be applied and the timeAlignmentTimerassociated with this TAG started. When the contention resolution isconsidered not successful, a timeAlignmentTimer associated with this TAGmay be stopped. Otherwise, the MAC entity may ignore the received TimingAdvance Command.

In example embodiments, a timer is running once it is started, until itis stopped or until it expires; otherwise it may not be running. A timercan be started if it is not running or restarted if it is running. Forexample, a timer may be started or restarted from its initial value.

Example embodiments of the invention may enable operation ofmulti-carrier communications. Other example embodiments may comprise anon-transitory tangible computer readable media comprising instructionsexecutable by one or more processors to cause operation of multi-carriercommunications. Yet other example embodiments may comprise an article ofmanufacture that comprises a non-transitory tangible computer readablemachine-accessible medium having instructions encoded thereon forenabling programmable hardware to cause a device (e.g. wirelesscommunicator, UE, base station, etc.) to enable operation ofmulti-carrier communications. The device may include processors, memory,interfaces, and/or the like. Other example embodiments may comprisecommunication networks comprising devices such as base stations,wireless devices (or user equipment: UE), servers, switches, antennas,and/or the like.

The amount of data traffic carried over cellular networks is expected toincrease for many years to come. The number of users/devices isincreasing, and each user/device accesses an increasing number andvariety of services, e.g. video delivery, large files, images. Thisrequires not only high capacity in the network, but also provisioningvery high data rates to meet customers' expectations on interactivityand responsiveness. More spectrum is therefore needed for cellularoperators to meet the increasing demand. Considering user expectationsof high data rates along with seamless mobility, it is beneficial thatmore spectrum be made available for deploying macro cells as well assmall cells for cellular systems.

Striving to meet the market demands, there has been increasing interestfrom operators in deploying some complementary access utilizingunlicensed spectrum to meet the traffic growth. This is exemplified bythe large number of operator-deployed Wi-Fi networks and the 3GPPstandardization of LTE/WLAN interworking solutions. This interestindicates that unlicensed spectrum, when present, can be an effectivecomplement to licensed spectrum for cellular operators to helpaddressing the traffic explosion in some scenarios, such as hotspotareas. LAA offers an alternative for operators to make use of unlicensedspectrum while managing one radio network, thus offering newpossibilities for optimizing the network's efficiency.

In an example embodiment, Listen-before-talk (clear channel assessment)may be implemented for transmission in an LAA cell. In alisten-before-talk (LBT) procedure, equipment may apply a clear channelassessment (CCA) check before using the channel. For example, the CCAutilizes at least energy detection to determine the presence or absenceof other signals on a channel in order to determine if a channel isoccupied or clear, respectively. For example, European and Japaneseregulations mandate the usage of LBT in the unlicensed bands. Apart fromregulatory requirements, carrier sensing via LBT may be one way for fairsharing of the unlicensed spectrum.

In an example embodiment, discontinuous transmission on an unlicensedcarrier with limited maximum transmission duration may be enabled. Someof these functions may be supported by one or more signals to betransmitted from the beginning of a discontinuous LAA downlinktransmission. Channel reservation may be enabled by the transmission ofsignals, by an LAA node, after gaining channel access via a successfulLBT operation, so that other nodes that receive the transmitted signalwith energy above a certain threshold sense the channel to be occupied.Functions that may need to be supported by one or more signals for LAAoperation with discontinuous downlink transmission may include one ormore of the following: detection of the LAA downlink transmission(including cell identification) by UEs; time & frequency synchronizationof UEs.

In an example embodiment, DL LAA design may employ subframe boundaryalignment according to LTE-A carrier aggregation timing relationshipsacross serving cells aggregated by CA. This may not imply that the eNBtransmissions can start only at the subframe boundary. LAA may supporttransmitting PDSCH when not all OFDM symbols are available fortransmission in a subframe according to LBT. Delivery of necessarycontrol information for the PDSCH may also be supported.

LBT procedure may be employed for fair and friendly coexistence of LAAwith other operators and technologies operating in unlicensed spectrum.LBT procedures on a node attempting to transmit on a carrier inunlicensed spectrum require the node to perform a clear channelassessment to determine if the channel is free for use. An LBT proceduremay involve at least energy detection to determine if the channel isbeing used. For example, regulatory requirements in some regions, e.g.,in Europe, specify an energy detection threshold such that if a nodereceives energy greater than this threshold, the node assumes that thechannel is not free. While nodes may follow such regulatoryrequirements, a node may optionally use a lower threshold for energydetection than that specified by regulatory requirements. In an example,LAA may employ a mechanism to adaptively change the energy detectionthreshold, e.g., LAA may employ a mechanism to adaptively lower theenergy detection threshold from an upper bound. Adaptation mechanism maynot preclude static or semi-static setting of the threshold. In anexample Category 4 LBT mechanism or other type of LBT mechanisms may beimplemented.

Various example LBT mechanisms may be implemented. In an example, forsome signals, in some implementation scenarios, in some situations,and/or in some frequencies no LBT procedure may performed by thetransmitting entity. In an example, Category 2 (e.g. LBT without randomback-off) may be implemented. The duration of time that the channel issensed to be idle before the transmitting entity transmits may bedeterministic. In an example, Category 3 (e.g. LBT with random back-offwith a contention window of fixed size) may be implemented. The LBTprocedure may have the following procedure as one of its components. Thetransmitting entity may draw a random number N within a contentionwindow. The size of the contention window may be specified by theminimum and maximum value of N. The size of the contention window may befixed. The random number N may be employed in the LBT procedure todetermine the duration of time that the channel is sensed to be idlebefore the transmitting entity transmits on the channel. In an example,Category 4 (e.g. LBT with random back-off with a contention window ofvariable size) may be implemented. The transmitting entity may draw arandom number N within a contention window. The size of contentionwindow may be specified by the minimum and maximum value of N. Thetransmitting entity may vary the size of the contention window whendrawing the random number N. The random number N is used in the LBTprocedure to determine the duration of time that the channel is sensedto be idle before the transmitting entity transmits on the channel.

LAA may employ uplink LBT at the UE. The UL LBT scheme may be differentfrom the DL LBT scheme (e.g. by using different LBT mechanisms orparameters) for example, since the LAA UL is based on scheduled accesswhich affects a UE's channel contention opportunities. Otherconsiderations motivating a different UL LBT scheme include, but are notlimited to, multiplexing of multiple UEs in a single subframe.

In an example, a DL transmission burst may be a continuous transmissionfrom a DL transmitting node with no transmission immediately before orafter from the same node on the same CC. An UL transmission burst from aUE perspective may be a continuous transmission from a UE with notransmission immediately before or after from the same UE on the sameCC. In an example, UL transmission burst is defined from a UEperspective. In an example, an UL transmission burst may be defined froman eNB perspective. In an example, in case of an eNB operating DL+UL LAAover the same unlicensed carrier, DL transmission burst(s) and ULtransmission burst(s) on LAA may be scheduled in a TDM manner over thesame unlicensed carrier. For example, an instant in time may be part ofa DL transmission burst or an UL transmission burst.

The amount of data traffic carried over cellular networks is expected toincrease for many years to come. The number of users/devices isincreasing, and a user/device accesses an increasing number and varietyof services, e.g. video delivery, large files, images. This may requirehigh capacity in the network, and may provision high data rates to meetcustomers' expectations on interactivity and responsiveness. Morespectrum is therefore needed for cellular operators to meet theincreasing demand. Considering user expectations of high data ratesalong with seamless mobility, it may be beneficial that more spectrum bemade available for deploying macro cells as well as small cells forwireless systems.

Striving to meet the market demands, there has been increasing interestfrom operators in deploying some complementary access utilizingunlicensed spectrum to meet the traffic growth. This is exemplified bythe large number of operator-deployed Wi-Fi networks and the 3GPPstandardization of LTE/WLAN interworking solutions. This interestindicates that unlicensed spectrum, when present, may be an effectivecomplement to licensed spectrum for cellular operators to helpaddressing the traffic explosion in some scenarios, such as hotspotareas. LAA offers an alternative for operators to make use of unlicensedspectrum while managing one radio network, thus offering newpossibilities for optimizing the network's efficiency.

In an example embodiment, Listen-before-talk (clear channel assessment)may be implemented for transmission in an LAA cell. In alisten-before-talk (LBT) procedure, equipment may apply a clear channelassessment (CCA) check before using the channel. For example, the CCAutilizes at least energy detection to determine the presence or absenceof other signals on a channel in order to determine if a channel isoccupied or clear, respectively. For example, European and Japaneseregulations mandate the usage of LBT in the unlicensed bands. Apart fromregulatory requirements, carrier sensing via LBT may be one way for fairsharing of the unlicensed spectrum.

In an example embodiment, discontinuous transmission on an unlicensedcarrier with limited maximum transmission duration may be implemented.Some of these functions may be implemented by one or more signals to betransmitted from the beginning of a discontinuous LAA downlinktransmission. Channel reservation may be enabled by the transmission ofsignals, by an LAA node, after gaining channel access via a successfulLBT operation, so that other nodes that receive the transmitted signalwith energy above a certain threshold sense the channel to be occupied.Functions that may need to be implemented by one or more signals for LAAoperation with discontinuous downlink transmission may include one ormore of the following: detection of the LAA downlink transmission (e.g.including cell identification) by UEs; and/or time & frequencysynchronization of UEs.

Frame structure type 3 may be applicable to an LAA cell operation e.g.with normal cyclic prefix. In an example, a radio frame may beT_f=307200*T_s=10 ms long and include 20 slots of lengthT_slot=15360*T_s=0.5 ms, numbered from 0 to 19. A subframe may comprisetwo consecutive slots where subframe i comprises of slots 2i and 2i+1.The 10 subframes within a radio frame are available for downlink and/oruplink transmissions. Downlink transmissions may occupy one or moreconsecutive subframes, starting within a subframe and ending with thelast subframe either fully occupied or following one of the DwPTSdurations implemented in frame structure 2 (TDD). Uplink transmissionsmay occupy one or more consecutive subframes.

In an example, carrier aggregation including at least one cell operatingin the unlicensed spectrum may be to referred to as Licensed-AssistedAccess (LAA). In LAA, the configured set of serving cells for a UE mayinclude at least one SCell operating in the unlicensed spectrumaccording to Frame Structure 3, (e.g. LAA SCell).

In an example, LAA eNB and UE may apply Listen-Before-Talk (LBT) beforeperforming a transmission on LAA SCell. When LBT is applied, thetransmitter listens to/senses the channel to determine whether thechannel is free or busy. If the channel is determined to be free, thetransmitter may perform the transmission; otherwise, it does not performthe transmission. If an LAA eNB uses channel access signals of othertechnologies for the purpose of LAA channel access, it may continue tomeet the LAA maximum energy detection threshold requirement. Which LBTtype (e.g. Cat.4 LBT or 25 microseconds LBT) the UE applies may besignalled via uplink grant for uplink PUSCH transmission on LAA SCells.

In an example, for LAA, four Channel Access Priority Classes may bedefined which may be used when performing uplink and downlinktransmissions in LAA carriers. A pre-defined channel Access priorityclass may be used by traffic belonging to the different QCIs. The eNBmay configure whether the data of a logical channel may be transferredvia LAA SCells or not. For transmissions on serving cells operatingaccording to Frame Structure Type 3, the MAC entity may consider logicalchannels for which laa-Allowed (e.g. in an RRC message) has beenconfigured. The physical layer may perform a listen-before-talkprocedure, according to which transmissions are not performed if thechannel is identified as being occupied. In this case a MAC entity mayconsider the transmission to have been performed anyway.

In an example embodiment, DL LAA design may employ subframe boundaryalignment according to LTE-A carrier aggregation timing relationshipsacross serving cells aggregated by CA. This may not imply that the eNBtransmissions may start only at the subframe boundary. LAA may supporttransmitting PDSCH when not all OFDM symbols are available fortransmission in a subframe according to LBT. Delivery of necessarycontrol information for the PDSCH may also be supported.

LBT procedure may be employed for fair and friendly coexistence of LAAwith other operators and technologies operating in unlicensed spectrum.LBT procedures on a node attempting to transmit on a carrier inunlicensed spectrum require the node to perform a clear channelassessment to determine if the channel is free for use. An LBT proceduremay involve at least energy detection to determine if the channel isbeing used. For example, regulatory requirements in some regions, e.g.,in Europe, specify an energy detection threshold such that if a nodereceives energy greater than this threshold, the node assumes that thechannel is not free. While nodes may follow such regulatoryrequirements, a node may optionally use a lower threshold for energydetection than that specified by regulatory requirements. In an example,LAA may employ a mechanism to adaptively change the energy detectionthreshold, e.g., LAA may employ a mechanism to adaptively lower theenergy detection threshold from an upper bound. Adaptation mechanism maynot preclude static or semi-static setting of the threshold. In anexample Category 4 LBT mechanism or other type of LBT mechanisms may beimplemented.

Various example LBT mechanisms may be implemented. In an example, forsome signals, in some implementation scenarios, in some situations,and/or in some frequencies no LBT procedure may performed by thetransmitting entity. In an example, Category 2 (e.g. LBT without randomback-off) may be implemented. The duration of time that the channel issensed to be idle before the transmitting entity transmits may bedeterministic. In an example, Category 3 (e.g. LBT with random back-offwith a contention window of fixed size) may be implemented. An exampleLBT procedure may have the following procedure. The transmitting entitymay draw a random number N within a contention window. The size of thecontention window may be specified by the minimum and maximum value ofN. The size of the contention window may be fixed. The random number Nmay be employed in the LBT procedure to determine the duration of timethat the channel is sensed to be idle before the transmitting entitytransmits on the channel. In an example, Category 4 (e.g. LBT withrandom back-off with a contention window of variable size) may beimplemented. The transmitting entity may draw a random number N within acontention window. The size of contention window may be specified by theminimum and maximum value of N. The transmitting entity may vary thesize of the contention window when drawing the random number N. Therandom number N is used in the LBT procedure to determine the durationof time that the channel is sensed to be idle before the transmittingentity transmits on the channel.

LAA may employ uplink LBT at the UE. The UL LBT scheme may be differentfrom the DL LBT scheme (e.g. by using different LBT mechanisms orparameters) for example, since the LAA UL is based on scheduled accesswhich affects a UE's channel contention opportunities. Otherconsiderations motivating a different UL LBT scheme include, but are notlimited to, multiplexing of multiple UEs in a single subframe.

In an example, a DL transmission burst may be a continuous transmissionfrom a DL transmitting node with no transmission immediately before orafter from the same node on the same CC. An UL transmission burst from aUE perspective may be a continuous transmission from a UE with notransmission immediately before or after from the same UE on the sameCC. In an example, UL transmission burst may be defined from a UEperspective. In an example, an UL transmission burst may be defined froman eNB perspective. In an example, in case of an eNB operating DL+UL LAAover the same unlicensed carrier, DL transmission burst(s) and ULtransmission burst(s) on LAA may be scheduled in a TDM manner over thesame unlicensed carrier. For example, an instant in time may be part ofa DL transmission burst or an UL transmission burst.

In an example, DCI format 1C may be used for LAA common information. Thefollowing information is transmitted by means of the DCI format 1C:Subframe configuration for LAA (e.g. 4 bits), Uplink transmissionduration and offset indication (e.g. 5 bits), PUSCH trigger B (e.g. 1bit), reserved information bits.

DCI format 0A may be used for the scheduling of PUSCH in a LAA SCell.The following information may be transmitted by means of the DCI format0A: Carrier indicator (e.g. 0 or 3 bits). Flag for format0A/format1Adifferentiation (e.g. 1 bit, where value 0 indicates format 0A and value1 indicates format 1A.), PUSCH trigger A (e.g. 1 bit, where value 0indicates non-triggered scheduling and value 1 indicates triggeredscheduling), Timing offset (e.g. 4 bits, When the flag for triggeredscheduling is set to 0, The field indicates the absolute timing offsetfor the PUSCH transmission. Otherwise, The first two bits of the fieldindicate the relative timing offset for the PUSCH transmission. The lasttwo bits of the field indicate the time window within which thescheduling of PUSCH via triggered scheduling is valid.), resource blockassignment (e.g. 6 bits provide the resource allocation in the ULsubframe), Modulation and coding scheme (e.g. 5 bits), HARQ processnumber (e.g. 4 bits), New data indicator (e.g. 1 bit), Redundancyversion (e.g. 2 bits), TPC command for scheduled PUSCH (e.g. 2 bits),Cyclic shift for DM RS and OCC index (e.g. 3 bits), CSI request (e.g. 1,2 or 3 bits), SRS request (e.g. 1 bit), PUSCH starting position (e.g. 2bits, 00: symbol 0, 01: 25 μs in symbol 0, 10: (25+TA) μs in symbol 0,11: symbol 1), PUSCH ending symbol (1 bit, where value 0 indicates thelast symbol of the subframe and value 1 indicates the second to lastsymbol of the subframe.), Channel Access type (e.g. 1 bit), ChannelAccess Priority Class (e.g. 2 bits), and/or other fields.

DCI format 0B may be used for the scheduling of PUSCH in each ofmultiple subframes in a LAA SCell. The following information istransmitted by means of the DCI format 0B: Carrier indicator (e.g. 0 or3 bits), PUSCH trigger A (e.g. 1 bit, where value 0 indicatesnon-triggered scheduling and value 1 indicates triggered scheduling),Timing offset (e.g. 4 bits, when the flag for triggered scheduling isset to 0, the field indicates the absolute timing offset for the PUSCHtransmission. Otherwise, The first two bits of the field indicate therelative timing offset for the PUSCH transmission. The last two bits ofthe field indicate the time window within which the scheduling of PUSCHvia triggered scheduling is valid.), Number of scheduled subframes (e.g.1 or 2 bits. The 1-bit field applies whenmaxNumberOfSchedSubframes-Format0B is configured by higher layers totwo, otherwise the 2-bit field applies.), Resource block assignment(e.g. 6 bits provide the resource allocation in the UL subframe),Modulation and coding scheme (e.g. 5 bits), HARQ process number (e.g. 4bits. The 4-bit applies to the first scheduled subframe, and the HARQprocess numbers for other scheduled subframes are sequentiallyincremented module max HARQ ID), New data indicator (e.g.maxNumberOfSchedSubframes-Format0B-r14 bits. Each scheduled PUSCH maycorrespond to 1 bit.), Redundancy version (e.g.maxNumberOfSchedSubframes-Format0B bits. Each scheduled PUSCHcorresponds to 1 bit), TPC command for scheduled PUSCH (e.g. 2 bits),Cyclic shift for DM RS and OCC index (e.g. 3 bits), CSI request (e.g. 1,2 or 3 bits), SRS request (e.g. 2 bits), PUSCH starting position (e.g. 2bits as defined for DCI format 0A), PUSCH ending symbol (e.g. 1 bit,where value 0 indicates the last symbol of the last scheduled subframeand value 1 indicates the second last symbol of the last scheduledsubframe.), Channel Access type (e.g. 1 bit), Channel Access PriorityClass (e.g. 2 bits), and/or other parameters.

DCI format 4A may be used for the scheduling of PUSCH in a LAA SCellwith multi-antenna port transmission mode. DCI format 4B may be used forthe scheduling of PUSCH with multi-antenna port transmission mode ineach of multiple subframes in a LAA SCell.

In an example embodiment, DCI 0A/4A/0B/4B may include a bit to indicatewhether the UL grant is a triggered grant or not. If it is a triggeredgrant, the UE may transmit after receiving a 1 bit trigger in the PDCCHDCI scrambled with CC-RNTI in a subframe received after the subframecarrying the UL grant. The timing between the 2nd trigger transmitted insubframe N and an earliest UL transmission may be a UE capability, ifthe earliest UL transmission is before subframe N+4 (UE capabilitysignaling between transmission in subframe N+1 and N+2 and N+3).

In an example embodiment, the 4 bit field ‘SF timing’ in DCI format0A/4A/0B/4B for the triggered grant may be used as follows: When the UEmay transmit after reception of the trigger is signaled to the UE. 2bits may be used to indicate X. When a UE receives a trigger in subframeN, the UE may be allowed to start transmission in subframe N+X+Y.X={0,1,2,3} indicated reusing two bits in the DCI. Y may be given by theUL burst offset in the C-PDCCH DCI scrambled by CC-RNTI (e.g. in thesame subframe where the trigger is transmitted). The UE may receivesignaling in the first DCI 0A/4A/0B/4B grant indicating the number ofsubframes after which the grant becomes invalid reusing 2 bits. Theinitial grant may become invalid if M ms after the initial grant, novalid trigger has been received. 2 bit: M={8,12,16,20}. UE may followthe LBT type indicated by the UL grant. An eNB may signal in the uplinkgrant LBT type at least including 25 us single slot LBT and Cat4 LBT tothe UE at least for PUSCH.

In an example embodiment, C(common)-PDCCH may indicate a pair of values(UL burst duration, offset). UL burst duration may be a number ofconsecutive UL subframes belonging to the same channel occupancy, withthe DL subframes in the same channel occupancy signaling the UL burstduration. Offset may be the number of subframes to the start ofindicated UL burst from the start of the subframe carrying the C-PDCCH.

In an example embodiment, an LBT procedure for any UL subframe from thesubframe in which C-PDCCH was received up to and including subframesuntil the end of the signaled UL burst duration, for which the eNB hadalready indicated to perform Category 4 LBT, may be switched to an LBTbased on 25 us CCA. In an example, a UE may not switch to 25 us CCA ifpart of a set of contiguously scheduled subframes without gap appears inthe UL burst indication. The UE may not be required to receive any DLsignals/channels in a subframe indicated to be a UL subframe on thecarrier. 5 bits to indicate combinations of offset and burst duration.The code points include {offset, duration} combinations as follows:combinations of {{1, 2, 3, 4, 6}, {1, 2, 3, 4, 5, 6}}, Reserved, nosignaling of burst and offset. The format of the bits may be definedaccording to a pre-defined table.

In an example embodiment, resource allocation field in DCI 0A/4A/0B/4Bmay be 6 bits. The 64 code points indicated by the 6 bits may includethe legacy RIV for contiguous interlace allocation except the codepoints for the allocation of 7 contiguous interlaces (70 PRBs). This setof code points may include 51 values. Additional code points may bedefined for allocation of interlaces as follows: 0,1,5,6; 2,3,4,7,8,9;0, 5; 1, 6; 2, 7; 3, 8; 4, 9; 1, 2, 3, 4, 6, 7, 8, 9. Remaining codepoints may be reserved.

A UE may Support UL/DL Scheduling Combinations: Self-scheduling on DLand cross-carrier scheduling on UL. The UE to monitor for DCI formatsscheduling PUSCH of a single eLAA Scell on one UL licensed-bandscheduling cell, e.g. DCI formats 0A/0B, Formats 4A/4B (e.g. ifconfigured for TM2). The UE may monitor for DCI formats scheduling LAAPDSCH on the LAA SCell, e.g. DCI formats 1A/1B/1D/1/2A/2/2B/2C/2D. In anexample, the RRC signaling and cross carrier scheduling may be enhanced.RRC signaling may configure self-scheduling for DL and cross-carrierscheduling for UL, for example for an LAA cell. For example, a parameterin the cross-carrier scheduling configuration parameters may indicatewhether the cross carrier scheduling is for both downlink scheduling anduplink scheduling or is only for uplink scheduling (and DL isself-scheduled). In an example, a licensed cell may be configured forcross-carrier scheduling an unlicensed (e.g. LAA) cell.

For eLAA PUSCH transmission, one interlace may be the basic unit ofresource allocation, which may be composed of 10 RBs for 20 MHz. The 10RBs may be spaced equally in frequency domain for 20 MHz. In an examplefor 20 MHz eLAA SCell: interlace 0 is composed of RBs 0,10,20, . . .,90. A UE may be assigned one or more interlaces. The number of RBs usedfor transmission may be a multiple of 2,3 and 5.

In an example, One interlace may be composed of 10 RB/interlace for 10MHz. In an example, if the UE fails to complete Cat. 4 LBT for the firstsubframe in a multi-subframe UL grant, it may continue the Cat. 4 LBTprocedure and attempt transmission for subsequent subframes. In anexample embodiment, for enabling the start times within the firstDFTS-OFDM symbol, a longer cyclic prefix for the next DFTS-OFDM symbolto occupy part of the first DFTS-OFDM symbol may be used. The UE may notbe expected to start a new transmission subject to LBT earlier than 1DFTS-OFDM symbol after the end of the previous transmission by the UE.

For eLAA, flexible timing between UL grant and UL transmission may besupported. For UL grant(s) for a UE in a subframe enabling PUSCHtransmission for the UE in multiple subframes in LAA SCell, at leastsome of the following options are considered: 1) Single UL grant in asubframe for a UE may schedule N (N≥1) PUSCH transmissions for the UE inN subframes with single PUSCH per subframe. N is consecutive ornon-consecutive. 2) Single UL grant in a subframe for a UE may schedulesingle PUSCH transmission in a single subframe while UE may receivemultiple UL grants in a subframe for PUSCH transmissions in differentsubframes. 3) Single UL grant in a subframe for a UE may enable the UEto transmit single PUSCH transmission among one of the multiplesubframes depending on UL LBT result. In an example embodiment, for ULtransmission in eLAA Scells, flexible timing between the subframecarrying the UL grant and subframe(s) of the corresponding PUSCH(s) maybe implemented. In enhanced LAA, UL grant(s) for a UE in a subframe mayenable PUSCH transmission for the UE in multiple subframes in LAA SCellfor both cross-cc scheduling case and self-scheduling case.

In an example embodiment, DCI format(s) may have the followingscheduling information types: Type A: common to the scheduled subframes(appearing only once in a DCI), carrier indicator, resource assignment,Cyclic shift for DM RS and OCC index. Type B: subframe specificinformation (appearing N times for N subframes scheduling), RV, and NDI.

In an example, DCI format 0B/4B may indicates number of consecutivescheduled subframes. DCI format 0B/4B indicates HARQ process IDs for thescheduled subframes by indicating HARQ process ID for a startingsubframe, and HARQ p_ids for other subframes are derived by a givenrule. the HARQ p_ids for other subframes may be consecutive with theindicated HARQ process IDs, modulo max number of HARQ processes. DCIformat 0B/4B indicates RVs for the scheduled subframes by indicating a1-bit RV value per scheduled subframe (regardless of the number ofscheduled transport blocks). In an example, DCI may indicate RV 0 or 2.

A UE may Support UL/DL Scheduling Combinations: Self-scheduling on DLand cross-carrier scheduling on UL. The UE to monitor for DCI formatsscheduling PUSCH of a single eLAA Scell on one UL licensed-bandscheduling cell, e.g. DCI formats 0A/0B, Formats 4A/4B (e.g. ifconfigured for TM2). The UE may monitor for DCI formats scheduling LAAPDSCH on the LAA SCell, e.g. DCI formats 1A/1B/1D/1/2A/2/2B/2C/2D. In anexample, RRC signaling may configure self-scheduling on DL andcross-carrier scheduling on UL.

DCI format 0B/4B may schedule PUSCH transmission in a single subframe.For DCI format 0B/4B, bit width of number of scheduled subframes is 1bit when N_sf is configured as 2 and 2 bits when N_sf is configured aslarger than 2. Timing offset is counted from subframe N+4+k, and k issignalled with 4 bits ([0 . . . 15] SFs) (e.g. in case of 2-stepscheduling).

One of four starting symbol positions may be signaled for the firstsubframe in DCI formats 0A/4A/0B/4B. DCI including uplink grant mayindicate the starting time for transmission on UL, e.g. a field in a DCImay indicate starting at one of the following times in a UL subframe:Start of DFTS-OFDM symbol 0, Start of DFTS-OFDM symbol 1, 25 us afterstart of DFTS-OFDM symbol 0, 25 us+TA value after start of DFTS-OFDMsymbol 0. Extension of cyclic prefix of the next DFTS-OFDM symbol mayoccupy part of the first DFTS-OFDM symbol.

In an example embodiment, if a UE detects PDCCH with DCI CRC scrambledby CC-RNTI in subframe n−1 or subframe n of a LAA Scell, the UE mayassume the configuration of occupied OFDM symbols in subframe n of theLAA Scell according to the ‘Subframe configuration for LAA’ field in thedetected DCI in subframe n−1 or subframe n.

The subframe-configuration-for-LAA field indicates the configuration ofoccupied OFDM symbols (e.g., OFDM symbols used for transmission ofdownlink physical channels and/or physical signals) in current and/ornext subframe e.g. according to a predefined.

If the configuration of occupied OFDM symbols for subframe n isindicated by the Subframe configuration for LAA field in both subframen−1 and subframe n, the UE may assume that the same configuration ofoccupied OFDM symbols is indicated in both subframe n−1 and subframe n.

If a UE detects PDCCH with DCI CRC scrambled by CC-RNTI in subframe n,and the UE does not detect PDCCH with DCI CRC scrambled by CC-RNTI insubframe n−1, and if the number of occupied OFDM symbols for subframe nindicated by the Subframe configuration for LAA field in subframe n isless than 14, the UE may not be required to receive any other physicalchannels in subframe n.

If a UE does not detect PDCCH with DCI CRC scrambled by CC-RNTIcontaining ‘Subframe Configuration for LAA’ field set to other than‘1110’ and ‘1111’ in subframe n and the UE does not detect PDCCH withDCI CRC scrambled by CC-RNTI containing ‘Subframe Configuration for LAA’field set to other than ‘1110’ and ‘1111’ in subframe n−1, the UE is notrequired to use subframe n for updating CSI measurement.

If a serving cell is a LAA Scell, and if the higher layer parametersubframeStartPosition for the Scell indicates ‘s07’, and if the UEdetects PDCCH/EPDCCH intended for the UE starting in the second slot ofa subframe, the UE may assume that OFDM symbols in the first slot of thesubframe are not occupied, and OFDM symbols in the second slot of thesubframe are occupied. If subframe n is a subframe in which OFDM symbolsin the first slot are not occupied, the UE may assume that all the OFDMsymbols are occupied in subframe n+1.

If a UE is configured with a LAA SCell for UL transmissions, and the UEdetects PDCCH with DCI CRC scrambled by CC-RNTI in subframe n, the UEmay be configured with a ‘UL duration’ and ‘UL offset’ for subframe naccording to the Uplink-configuration-for-LAA field in the detected DCI.The uplink-configuration-for-LAA field indicates the UL duration and ULoffset, e.g. according to a table. For example, value of ‘ULconfiguration for LAA’ field 00001 may indicate UL offset of 1 subframeand UL duration of 1 subframe, value of ‘UL configuration for LAA’ field00010 may indicate UL offset of 1 subframe and UL duration of 2subframes, and continue to value of ‘UL configuration for LAA’ field11110 may indicate UL offset of 6 subframes and UL duration of 6subframes.

If the ‘UL configuration for LAA’ field configures an ‘UL offset’ ^(l)and an ‘UL duration’ ^(d) for subframe n, the UE is not required toreceive any downlink physical channels and/or physical signals insubframe(s) n+1+i with i=0, 1, . . . , d−1.

In an example embodiment, an eNB may transmit one or more RRC messagecomprising configuration parameters of a plurality of cells comprisingone or more licensed cells and/or one or more unlicensed (e.g. LAA)cell. Example configuration parameters for an LAA cell may comprise MAC,and PHY layer parameters. For example, PDSCH, PUSCH, PDCCH and otherdownlink and uplink channel parameters. Example configuration parametersmay include LBT configuration parameters, for example,maxEnergyDetectionThreshold IE may Indicate absolute maximum energydetection threshold values. For example, Value −85 to −85 dBm, and so on(e.g. in steps of 1 dB). If the field is absent, the UE may use adefault maximum energy detection threshold value. For example,energyDetectionThresholdOffset IE may indicates the offset to thedefault maximum energy detection threshold value. For example, Value −13to −13 dB, value −14 to −14 dB, and so on (e.g. in steps of 1 dB).

Example embodiments enhances PHY, MAC, and/RRC procedures in an eNBand/or UE and improves battery power consumption, radio spectralefficiency, and scheduling efficiency when carrier aggregation and/ordual connectivity is implemented employing unlicensed (e.g. LAA cells).

In an example, E-UTRAN may support Dual Connectivity (DC) operationwhereby a multiple Rx/Tx UE in RRC_CONNECTED may be configured toutilize radio resources provided by two distinct schedulers, located intwo eNBs connected via a non-ideal backhaul over the X2 interface. Theoverall E-UTRAN architecture may be applicable for DC as well. eNBsinvolved in DC for a certain UE may assume two different roles: an eNBmay either act as an MeNB or as an SeNB. In DC a UE may be connected toone MeNB and one SeNB.

In an example, in DC, the radio protocol architecture that a particularbearer uses may depend on how the bearer is setup. Three bearer typesmay exist: MCG bearer, SCG bearer and split bearer. Those three bearertypes are depicted in Figure below. RRC may be located in MeNB and SRBsare always configured as MCG bearer type and therefore only use theradio resources of the MeNB.

In an example, DC may be described as having at least one bearerconfigured to use radio resources provided by the SeNB.

In an example, inter-eNB control plane signaling for DC may be performedby means of X2 interface signaling. Control plane signaling towards theMME may be performed by means of S1 interface signaling.

In an example, there may be only one S1-MME connection per DC UE betweenthe MeNB and the MME. eNB may be able to handle UEs independently, i.e.provide the PCell to some UEs while providing SCell(s) for SCG toothers. Each eNB involved in DC for a certain UE may control its radioresources and may be primarily responsible for allocating radioresources of its cells. Respective coordination between MeNB and SeNBmay be performed by means of X2 interface signaling.

In an example, Figure below shows C-plane connectivity of eNBs involvedin DC for a certain UE: the S1-MME may be terminated in MeNB and theMeNB and the SeNB may be interconnected via X2-C.

In an example, for dual connectivity two different user planearchitectures may be allowed: one in which the S1-U only terminates inthe MeNB and the user plane data is transferred from MeNB to SeNB usingthe X2-U, and a second architecture where the S1-U may terminate in theSeNB. In an example, the Figure below shows different U-planeconnectivity options of eNBs involved in DC for a certain UE.

In an example, different bearer options may be configured with differentuser plane architectures. U-plane connectivity may depend on the beareroption configured:

In an example, for MCG bearers, the S1-U connection for thecorresponding bearer(s) to the S-GW may be terminated in the MeNB. TheSeNB may not be involved in the transport of user plane data for thistype of bearer(s) over the Uu.

In an example, for split bearers, the S1-U connection to the S-GW may beterminated in the MeNB. PDCP data may be transferred between the MeNBand the SeNB via X2-U. The SeNB and MeNB are involved in transmittingdata of this bearer type over the Uu. In an example, for SCG bearers,the SeNB may be directly connected with the S-GW via S1-U. The MeNB maynot be involved in the transport of user plane data for this type ofbearer(s) over the Uu. In an example, if only MCG and split bearers areconfigured, there may be no S1-U termination in the SeNB. In an example,the following scenarios for Dual Connectivity involving HeNBs aresupported as listed in Table below.

In an example, membership Verification for the hybrid access HeNB may beperformed between the MeNB and the MME, and may be based on membershipstatus information reported by the UE and the CSG ID.

In an example, if the cell served by the SeNB is a shared hybrid cell,the UE may report the subset of the broadcasted PLMN identities passingPLMN ID check and the CSG whitelist of the UE includes an entrycomprising of the concerned PLMN identity and the CSG ID broadcast bythe cell served by the SeNB. The MeNB may perform PLMN ID check for thePLMNs reported by the UE and may select one if multiple pass the PLMN IDcheck. If the cell served by the SeNB belongs to a different PLMN thanthe PLMN serving for the UE in the MeNB, the information provided to theMME for membership verification may need to contain the PLMN-ID of thehybrid cell served by the SeNB. The MME may verify the CSG membershipaccording to the received CSG ID, the selected PLMN ID and storedsubscription CSG information of the UE.

In an example, in case the UE has been admitted with SCG resourcesconfigured with the split bearer option from a hybrid HeNB and a SeNBChange may be performed within the coverage area of the MeNB towardsanother hybrid HeNB which has the same CSG ID as the first one, the MeNBmay re-use the result of the membership verification performed for thefirst HeNB.

In an example, in case of DC, the UE may be configured with two MACentities: one MAC entity for MeNB and one MAC entity for SeNB. TheExample Figure below describes the layer 2 structure for the downlinkwhen both CA and DC are configured. In order to simplify the figure, theBCH, PCH, MCH and corresponding logical channels are not included. Also,only UEn is shown as having DC configured.

The example Figure below describes the layer 2 structure for the uplinkwhen both CA and DC are configured. In an example, SRBs may be handledby the MeNB. For a split bearer, a UE may be configured over which link(or both) the UE transmits UL PDCP PDUs by the MeNB. In an example, onthe link which is not responsible for UL PDCP PDUs transmission, the RLClayer may transmit corresponding ARQ feedback for the downlink data.

In an example, in DC, the configured set of serving cells for a UE mayconsist of two subsets: the Master Cell Group (MCG) containing theserving cells of the MeNB, and the Secondary Cell Group (SCG) containingthe serving cells of the SeNB. In an example, when a UE is configuredwith CA in the MCG, the carrier aggregation principles may apply to MCG.

In an example, for SCG, the following principles may be applied: atleast one cell in SCG may have a configured UL CC and one of them, namedPSCell, may be configured with PUCCH resources; when SCG is configured,there may always be at least one SCG bearer or one Split bearer; upondetection of a physical layer problem or a random access problem onPSCell, or the maximum number of RLC retransmissions has been reachedassociated with the SCG, or upon detection of an access problem onPSCell (e.g., T307 expiry) during SCG change, or when exceeding themaximum transmission timing difference between CGs, RRC connectionRe-establishment procedure may not be triggered, UL transmissionstowards cells of the SCG may be stopped, MeNB may be informed by the UEof SCG failure type, and/or for split bearer the DL data transfer overthe MeNB may be maintained; the RLC AM bearer may be configured for thesplit bearer; like PCell, PSCell may not be de-activated; PSCell may bechanged with SCG change (e.g., with security key change and RACHprocedure); neither direct bearer type change between Split bearer andSCG bearer nor simultaneous configuration of SCG and Split bearer may besupported.

In an example, with respect to the interaction between MeNB and SeNB,the following principles may be applied: logical channel identities maybe independently allocated by the MeNB and the SeNB; the MeNB maymaintain the RRM measurement configuration of the UE and/or may, e.g.based on received measurement reports or traffic conditions or bearertypes, decide to ask a SeNB to provide additional resources (servingcells) for a UE; upon receiving the request from the MeNB, a SeNB maycreate the container that may result in the configuration of additionalserving cells for the UE (or decide that it has no resource available todo so); for UE capability coordination, the MeNB may provide (part of)the AS configuration and the UE capabilities to the SeNB; the MeNB andthe SeNB exchange information about UE configuration by means of RRCcontainers (inter-node messages) may be carried in X2 messages; the SeNBmay initiate a reconfiguration of its existing serving cells (e.g.,PUCCH towards the SeNB); the SeNB may decide which cell is the PSCellwithin the SCG; the MeNB may not change the content of the RRCconfiguration provided by the SeNB; in the case of the SCG addition andSCG SCell addition, the MeNB may provide the latest measurement resultsfor the SCG cell(s); and/or both MeNB and SeNB may know the SFN andsubframe offset of each other by OAM or UE measurement, e.g., for thepurpose of DRX alignment and identification of measurement gap.

In an example, when adding a new SCG SCell, dedicated RRC signaling maybe used for sending all required system information of the cell as forCA, except for the SFN acquired from MIB of the PSCell of SCG.

In an example, for Dual Connectivity, the UE may be configured with twocell groups (CGs). A CG may include cells that are associated to thesame eNB and those cells may be synchronized at the eNB level similar asfor carrier aggregation. In an example, two operations may be defined:synchronous and asynchronous DC. In synchronous DC operation, the UE maycope with a maximum reception timing difference up to at least 33 μs andmaximum transmission timing difference up to at least 35.21 μs betweenCGs. In asynchronous DC operation, the UE may cope with a maximumreception/transmission timing difference up to 500 μs between CGs.

In an example, When DC is deployed, frame timing and SFN are alignedamong the component carriers to be aggregated within a CG, and may ormay not be aligned between different CGs.

In an example, an LAA cell employing an unlicensed spectrum may havecell configurations different from legacy cells employing TDD and/or FDDsubframe structures. An LAA cell may employ a frame structure type 3and/or an LBT function. In legacy systems, base stations do not sharetheir LAA cell configuration information, such as frame structure type 3configurations, LBT functions, and/or the like, with their neighboringbase stations. By sharing cell configuration information for an LAAcell, neighboring base stations may determine whether their neighborcells are LAA cells or other type of cells, and further may be informeddetailed cell configuration parameters of neighboring LAA cells. Basedon the received cell configuration parameters of LAA cells, a basestation may update its cell configuration parameters, for example, to bealigned with the neighboring LAA cells, not to interfere the neighboringLAA cells' operation, to cooperate with the neighboring LAA cells, tocontrol network optimization operation (e.g. load balancing, mobility,interference, etc.), and/or the like.

In an example, based on the shared cell configuration parameters of LAAcells, a base station may make a decision of handover and/or dualconnectivity initiation/modification for a wireless device. In anexample, if a wireless device supports an unlicensed spectrum, a basestation may positively take into account a handover/dual-connectivity ofthe wireless device towards its neighboring base station with LAA cells.In an example, if a wireless device does not support an unlicensedspectrum, a base station may negatively consider ahandover/dual-connectivity of the wireless device towards itsneighboring base station with LAA cells.

In an example, based on the shared cell configuration parameters of LAAcells, a base station may configure one or more mobility parameterstowards a base station of the LAA cells. In an example, though non-LAAcells of a neighboring base station are in high load status, if theneighboring base station has an LAA cell, a base station may initiate ahandover towards the neighboring base station. In an example, a basestation may further transmit, to a wireless device, a measurementconfiguration message configured based on the shared cell configurationparameters of LAA cells. The measurement configuration message maycomprise measurement configurations for the neighboring LAA cells.

In an example embodiment, an issue with respect to exchanging anunlicensed/LAA cell information between eNBs is how an eNB recognizeswhether its neighbor cell supports unlicensed/LAA functions or notand/or how an eNB gets its neighbor unlicensed/LAA cell information thatmay be employed when the eNB decides an operation related to itsneighbor unlicensed/LAA cell. In an example, an unlicensed/LAA cell usesan unlicensed spectrum to exchange packets with a wireless device.Because the unlicensed spectrum may be shared with other networks, e.g.WLAN and/or other LTE networks, an unlicensed/LAA cell may require cellconfigurations, e.g. using frame structure type 3 and/or LBT function,distinguished from cell configurations for conventional FDD or TDDcells. In an example, to share the unlicensed spectrum with othernetworks, an eNB may use an LBT (Listen Before Talk) function, in whichthe eNB may detect energy level from other networks on its transmissionfrequency before transmitting packets through the frequency. In anexample, if the energy level detected is higher than a threshold, theeNB may not transmit packets.

In an example embodiment, an X2 setup request message and/or an X2 setupresponse message may comprise a global eNB ID, local home networkidentifier (LHN ID), a GU Group ID list (e.g. including all pools towhich an eNB belongs), and/or Served Cells (e.g. including informationof one or more serving cells) comprising a Served Cell Information and aNeighbour Information.

In an example embodiment, an eNB configuration update message maycomprise Served Cells To Add (e.g. including information of cellsstarting operation), Served Cells to Modify (e.g. including informationof one or more cells modifying operation), Served Cells to Delete (e.g.including information of one or more cells stopping operation), a GUGroup Id To Add List (e.g. including a list of one or more GU Group Idsto which an eNB may belong), a GU Group Id To Delete List (e.g.including a list of one or more GU Group Ids to which an eNB may notbelong anymore), and/or Coverage Modification List (e.g. including alist of one or more cells modifying coverage or inactivated and/orinformation of cell replacements). The list of Served Cells to Add maycomprise Served Cell Information and/or a list of Neighbour Information.The list of Served Cells to Modify may comprise an old E-UTRAN cellglobal identifier (Old ECGI), Served Cell Information, and/or a list ofNeighbour Information. The list of Served Cells to Delete may comprisean old E-UTRAN cell global identifier (Old ECGI).

In an example embodiment, the Served Cell Information of an X2 setuprequest/response message and/or an eNB configuration update message, maycomprise at least one of: physical cell id (PCI), evolved cell globalidentifier (ECGI), tracking area code, broadcast PLMN (e.g. including alist of one or more PLMN Identities), number of antenna ports, PRACHconfiguration parameters, MBSFN subframe information (e.g. includingradio frame allocation period, radio frame allocation offset, subframeallocation), closed subscriber group (CSG) identifier, MBMS service areaidentity list (e.g. including list of one or more MBMS Service AreaIdentities), multi band information list, frequency band indicatorpriority, and/or cell Configuration. the Served Cell Information maycomprise at least one of FDD cell information, TDD cell information,and/or unlicensed/LAA cell information.

In an example, the Neighbour Information of an X2 setup request/responsemessage and/or an eNB configuration update message may comprise evolvedcell global identifier (ECGI), physical cell identifier (PCI), E-UTRAabsolute radio frequency channel number (EARFCN) containing DL EARFCNfor FDD or EARFCN for TDD or unlicensed/LAA cell, tracking area code(TAC), and/or EARFCN Extension containing DL EARFCN for FDD or EARFCNfor TDD or unlicensed/LAA cell (if the EARFCN Extension is present, thevalue signaled in the EARFCN may be ignored).

In an example embodiment, an eNB may select/configure configurationparameters for its unlicensed/LAA cell and may transmit unlicensed/LAAcell information to its neighbor eNBs. In an example, the unlicensed/LAAcell information may comprise at least one of: physical cell id (PCI),evolved cell global identifier (ECGI), tracking area code, broadcastPLMN (e.g. including a list of one or more PLMN Identities), number ofantenna ports, PRACH configuration parameters, MBSFN subframeinformation (e.g. including radio frame allocation period, radio frameallocation offset, subframe allocation), closed subscriber group (CSG)identifier, MBMS service area identity list (e.g. including list of oneor more MBMS Service Area Identities), multi band information list,frequency band indicator priority, and/or cell configuration.

Cell configuration may indicate that the cell is an Unlicensed and/orLAA Cell type (e.g. using frame structure type 3). Cell configurationfor an TDD or FDD cell may indicate that the cell is a TDD cell type(e.g. using frame structure type 2) or FDD cell type (e.g. using framestructure type 1). In an example, a cell may be one of FDD, TDD, or LAAcell type.

Cell configuration for an Unlicensed and/or LAA Cell may compriseEARFCN, Transmission Bandwidth, and/or unlicensed/LAA-Cell-Configurationof the unlicensed/LAA cell. The EARFCN (E-UTRA Absolute Radio FrequencyChannel Number), for example, may define the carrier frequency used inthe unlicensed/LAA cell. The Transmission Bandwidth, for example, may beused to indicate uplink and/or downlink transmission bandwidth expressedin units of resource blocks.

In an example, the unlicensed/LAA-Cell-Configuration may comprisesubframeStartPosition (possible starting positions of transmission inthe first subframe of the DL transmission burst, e.g. Value s0 means thestarting position is subframe boundary, s07 means the starting positionis either subframe boundary or slot boundary), laa-SCellSubframeConfig(indication of whether a corresponding subframe is allocated as MBSFNsubframe or not), crossCarrierSchedulingConfigunlicensed/LAA-UL (aschedulingCellId indicated incrossCarrierSchedulingConfigunlicensed/LAA-UL may indicate which cellsignals uplink grants), lbt-Config comprisingmaxEnergyDetectionThreshold (absolute maximum energy detection thresholdvalues for LBT function) and/or energyDetectionThresholdOffset (offsetto corresponding default maximum energy detection threshold value),pdcch-Configunlicensed/LAA (comprising information of monitoring DCI),absenceOfAnyOtherTechnology (indicating absence or presence of any othernetwork sharing corresponding carrier), and/orsoundingRS-UL-ConfigDedlicatedAperiodic (comprising SRS subframeindication), other LBT configuration parameters (e.g. one or more LBTpriorities, LBT windows, LBT starting times, one or more LBT counters,and/or the like), LBT subframe configuration (e.g. subframe allocation,subframe offset, and/or subframe periodicity for LBT), maximum powertransmission, and/or maximum transmission burst duration.

In an example, LBT parameters may be coordinated among base stations.One base station may be a Master eNB and another base station may be theSlave eNB. An Slave eNB may determine LBT parameters based on theparameters received from a Master eNB. In an example, LBT parameterand/or subframe coordination may reduce interference in the network. TheeNBs may not compete for a channel at the same time and/or using thesame configuration parameters. The probability of channel access by aneNB/UE may increase due to the coordination. In an example, one eNBand/or UE may defer LBT after an LBT interval of another eNB and/or UE.In an example, an eNBs may coordinate LBT parameters for differentchannel access priorities. For example, LBT (channel access) parametersfor LBT priority 1 among eNBs may be coordinated. In an example, ahigher priority LBT of a first eNB may be prioritized over a lowerpriority of another base station. This may be performed consideringadjustment to LBT windows and/or LBT counters.

In an example embodiment, after receiving the unlicensed/LAA cellinformation of a neighbor cell from its neighbor eNB controlling theneighbor cell, an eNB may determine its further operation at least basedon one or more elements of the unlicensed/LAA cell information. In anexample, the eNB may configure its operation parameters (e.g.unlicensed/LAA cell configuration parameters, mobility parameters, dualconnectivity parameters, load balancing parameters, interference controlparameters, UE measurement configuration parameters, and/or other cellor UE control parameters) at least based on one or more elements of theunlicensed/LAA cell information.

In an example, an eNB may make a handover decision for a UE at leastbased on one or more elements of the unlicensed/LAA cell informationreceived from a neighbor eNB. For example, in case that a UE needsservices requiring stable data transmission rates, an eNB may avoid ahandover of the UE towards a neighbor eNB using unlicensed spectrums.For example, in case that a UE does not need services requiring stabledata transmission rates, an eNB may initiate a handover of the UEtowards a neighbor eNB using unlicensed spectrums by sending a handoverrequest message to the neighbor eNB. For example, even though a neighboreNB uses unlicensed spectrums and a UE needs services requiring stabledata transmission rates, an eNB may initiate a handover of the UEtowards the neighbor eNB if the absenceOfAnyOtherTechnology in theunlicensed/LAA cell information received from the neighbor eNB indicatesabsence of any other network sharing the unlicensed spectrums, bysending a handover request message to the neighbor eNB.

In an example, an eNB may make a dual connectivityinitiation/modification decision for a UE at least based on one or moreelements of the unlicensed/LAA cell information received from a neighboreNB. For example, in case that a bearer of a UE is for servicesrequiring stable data transmission rates, an eNB may avoid offloadingthe bearer towards an unlicensed/LAA cell of a neighbor eNB. Forexample, in case that a bearer of a UE is for services not requiringstable data transmission rates, an eNB may offload the bearer towards anunlicensed/LAA cell of a neighbor eNB by sending an SeNB additionrequest message or an SeNB modification request message to the neighboreNB. For example, even though a bearer of a UE is for services requiringstable data transmission rates, an eNB may offload the bearer towards anunlicensed/LAA cell of a neighbor eNB if the absenceOfAnyOtherTechnologyin the unlicensed/LAA cell information received from the neighbor eNBindicates absence of any other network sharing a spectrum of theunlicensed/LAA cell, by sending an SeNB addition request message or anSeNB modification request message to the neighbor eNB.

In an example, an eNB may update mobility parameters at least based onone or more elements of the unlicensed/LAA cell information receivedfrom a neighbor eNB. For example, if the absenceOfAnyOtherTechnology inthe unlicensed/LAA cell information received from a neighbor eNBindicates presence of any other network sharing a spectrum of aunlicensed/LAA cell of the neighbor eNB, an eNB may change mobilityparameters to reduce handover initiations towards the neighbor eNBoperating the corresponding unlicensed/LAA cell, and/or the eNB may senda mobility change request message to the neighbor eNB to notify theupdated mobility parameters. For example, if theabsenceOfAnyOtherTechnology in the unlicensed/LAA cell informationreceived from a neighbor eNB indicates absence of any other networksharing a spectrum of a unlicensed/LAA cell of the neighbor eNB, an eNBmay change mobility parameters to increase handover initiations towardsthe neighbor eNB operating the corresponding unlicensed/LAA cell, and/orthe eNB may send a mobility change request message to the neighbor eNBto notify the updated mobility parameters.

In an example, the mobility parameters may comprise a3-Offset,a5-Threshold1, a5-Threshold2, hysteresis for a3 and/or a5 event,timeToTrigger for a3 and/or a5 event, filtercoefficient for a3 and/or a5event, and/or cellIndividualOffset of a handover source cell and/or ahandover target cell for a3 and/or a5 event.

In an example, an eNB may request a measurement to a UE at least basedon one or more elements of the unlicensed/LAA cell information receivedfrom a neighbor eNB. For example, after receiving the unlicensed/LAAcell information from a neighbor eNB, an eNB may send, to a UE,measurement configuration parameters updated at least based on theEARFCN, the Transmission Bandwidth, and/or theunlicensed/LAA-Cell-Configuration in the unlicensed/LAA cellinformation. In an example, measurement configuration parameters may beconveyed via an RRCConnectionReconfiguration message or anRRCConnectionResume message.

In an example embodiment, in FIG. 10 , a first eNB may transmit a firstmessage to a second eNB. The second eNB may transmit a second message tothe first eNB. The first message, for example, may be an X2 setuprequest message, and the second message may be an X2 setup responsemessage, wherein the first message and the second message may beexchanged as a part of an X2 setup procedure. Through the X2 setupprocedure the first eNB and/or the second eNB may exchange applicationlevel configuration data needed to interoperate over an X2 interfacebetween the two eNBs. The first eNB may transfer a list of its servedcells and/or a list of supported GU Group Ids to the second eNB via thefirst message. The second eNB may reply with a list of its served cellsand/or a list of supported GU Group Ids in the second message. In anexample, the first message and/or the second message may comprise theunlicensed/LAA cell information, wherein the unlicensed/LAA cellinformation may comprise the EARFCN, the Transmission Bandwidth, and/orthe unlicensed/LAA-Cell-Configuration for an unlicensed/LAA celloperated by the message sending eNB. In an example, a served cellinformation IE in the X2 setup request message and/or the X2 setupresponse message may comprise the unlicensed/LAA cell information. In anexample, after receiving the unlicensed/LAA cell information, the firsteNB and/or the second eNB may initiate a UE handover, initiate/modify adual connectivity of a UE, update mobility parameters, initiate amobility setting change procedure, and/or transfer measurementconfiguration parameters to a UE at least based on one or more elementsof the unlicensed/LAA cell information.

In an example embodiment, FIG. 11 , a first eNB may transmit a firstmessage to a second eNB. The second eNB may transmit a second message tothe first eNB. The first message, for example, may be an eNBconfiguration update message, and the second message may be an eNBconfiguration update acknowledge message, wherein the first message andthe second message may be exchanged as a part of an eNB configurationupdate procedure. Through the eNB configuration update procedure, thefirst eNB and/or the second eNB may update application levelconfiguration data needed to interoperate over an X2 interface betweenthe two eNBs. The first message may comprise up-to-date configurationdata, e.g. lists of added, modified, and/or deleted served cells, thatthe first eNB may have taken into operational use. Upon reception of thefirst message, the second eNB may update information for the first eNB.In an example, the first message may comprise the unlicensed/LAA cellinformation, wherein the unlicensed/LAA cell information may comprisethe EARFCN, the Transmission Bandwidth, and/or theunlicensed/LAA-Cell-Configuration for an unlicensed/LAA cell operated bythe message sending eNB. In an example, a served cell information IE inthe eNB configuration update message may comprise the unlicensed/LAAcell information. In an example, after receiving the unlicensed/LAA cellinformation, the second eNB may initiate a UE handover, initiate/modifya dual connectivity of a UE, update mobility parameters, initiate amobility setting change procedure, and/or transfer measurementconfiguration parameters to a UE at least based on one or more elementsof the unlicensed/LAA cell information. In FIG. 12 , the first messagemay be a load information message, and/or the second message may not betransmitted.

In an example embodiment, in FIG. 13 , a first eNB may transmit a firstmessage to an MME. The MME may transmit a second message to a secondeNB. The first message, for example, may be an eNB configurationtransfer message, and the second message may be an MME configurationtransfer message. In an example, the first message may comprise theunlicensed/LAA cell information, wherein the unlicensed/LAA cellinformation may comprise the EARFCN, the Transmission Bandwidth, and/orthe unlicensed/LAA-Cell-Configuration for an unlicensed/LAA celloperated by the message sending eNB, and the second message may compriseone or more elements of the first message. In an example, afterreceiving the unlicensed/LAA cell information via the first message andthe second message, the second eNB may initiate a UE handover,initiate/modify a dual connectivity of a UE, update mobility parameters,initiate a mobility setting change procedure, and/or transfermeasurement configuration parameters to a UE at least based on one ormore elements of the unlicensed/LAA cell information.

In an example embodiment, in FIG. 14 , a first eNB may transmit a firstmessage to a first MME. The first MME may transmit a second message to asecond MME. The second MME may transmit a third message to a second eNB.The first message, for example, may be an eNB configuration transfermessage, the second message may be a configuration transfer tunnelmessage, and the third message may be an MME configuration transfermessage. In an example, the first message may comprise theunlicensed/LAA cell information, wherein the unlicensed/LAA cellinformation may comprise the EARFCN, the Transmission Bandwidth, and/orthe unlicensed/LAA-Cell-Configuration for an unlicensed/LAA celloperated by the message sending eNB, and the second message and thethird message may comprise one or more elements of the first message. Inan example, after receiving the unlicensed/LAA cell information via thefirst message, the second message, and the third message, the second eNBmay initiate a UE handover, initiate/modify a dual connectivity of a UE,update mobility parameters, initiate a mobility setting changeprocedure, and/or transfer measurement configuration parameters to a UEat least based on one or more elements of the unlicensed/LAA cellinformation.

In an example, a first base station may receive, from a second basestation, an application protocol message comprising: an identifier ofthe second base station, the second base station comprising a pluralityof cells comprising one or more unlicensed/licensed-assisted-access(unlicensed/LAA) cells; information identifying a cell type for each ofthe one or more unlicensed/LAA cells, the cell type being unlicensed/LAAtype; a cell identifier for each of the one or more unlicensed/LAAcells; and/or at least one unlicensed/LAA cell configuration parameterfor each of the one or more unlicensed/LAA cells. The first base stationmay operates/takes at least one of the following actions based, at leastin part, on information in the application protocol message: making ahandover decision for a wireless device; transmitting to the second basestation a second message comprising a handover request of a wirelessdevice towards the second base station; making a dual connectivityinitiation or modification decision for a bearer of a wireless device;transmitting to the second base station a second message comprising arequest for a dual connectivity initiation or modification for a bearerof a wireless device towards the second base station; transmitting tothe second base station a second message comprising updated mobilityparameters; and/or transmitting to a wireless device measurementconfiguration parameters for at least one of the one or moreunlicensed/LAA cells.

In an example, the at least one unlicensed/LAA cell configurationparameter may comprise at least one of: a subframeStartPosition; anlaa-SCellSubframeConfig; acrossCarrierSchedulingConfigunlicensed/LAA-UL; an lbt-Config comprisingone of maxEnergyDetectionThreshold or energyDetectionThresholdOffset; apdcch-Configunlicensed/LAA; an absenceOfAnyOtherTechnology; and/or asoundingRS-UL-ConfigDedicatedAperiodic.

In an example, the second base station may further transmit packetsemploying the at least one unlicensed/LAA cell configuration parametervia one or more unlicensed/LAA cells. In an example, the second basestation may further transmit, to a wireless device, one or more of theat least one unlicensed/LAA cell configuration parameter. The first basestation may receive the application protocol message from the secondbase station via one or more MMEs. In an example, the receiving of theapplication protocol message from the second base station is performedvia/employing one or more MMEs.

According to various embodiments, a device such as, for example, awireless device, off-network wireless device, a base station, and/or thelike, may comprise one or more processors and memory. The memory maystore instructions that, when executed by the one or more processors,cause the device to perform a series of actions. Embodiments of exampleactions are illustrated in the accompanying figures and specification.Features from various embodiments may be combined to create yet furtherembodiments.

FIG. 15 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 1510, a first base station may receive from asecond base station, cell configuration parameters of one or more cellsof the second base station. The cell configuration parameters maycomprise: at least one first information element (IE) indicating a firstidentifier of a first cell of the one or more cells; at least one secondIE indicating that the first cell is a licensed assisted access (LAA)cell; and at least one third IE indicating one or more configurationparameters of frame structure Type 3 of the LAA cell. At 1520, the firstbase station may make a handover decision for a first wireless devicebased on the one or more configuration parameters of frame structureType 3 of the LAA cell. At 1530, the first base station may send to thesecond base station, a handover request message for the first wirelessdevice in response to the handover decision.

According to an embodiment, the cell configuration parameters mayfurther comprise at least one of: at least one fourth IE indicating adownlink frequency; at least one fifth IE indicating an uplinkfrequency; at least one sixth IE indicating a downlink bandwidth; atleast one seventh IE indicating an uplink frequency, a combinationthereof, and/or the like.

According to an embodiment, the one or more configuration parameters offrame structure Type 3 of the LAA cell may indicate at least one of: anLAA cell subframe configuration; a subframe start position; a crosscarrier scheduling configuration unlicensed/LAA uplink; alisten-before-talk (LBT) configuration parameter comprising at least oneof a maximum energy detection threshold or an energy detection thresholdoffset; a physical downlink control channel (PDCCH) configurationunlicensed/LAA; a sounding reference signal uplink configurationdedicated aperiodic; an LBT procedure category comprising at least oneof category 2, category 3, or category 4; a size of contention windowfor an LBT procedure; a hybrid automated repeat request (HARD) processnumber; a maximum number of scheduled subframes; a multi-antenna porttransmission mode; a flexible timing support indication between uplinkgrant and uplink transmission, a combination thereof, and/or the like.

According to an embodiment, the first base station may further configureone or more mobility parameters towards a cell of the second basestation based on the one or more configuration parameters of framestructure Type 3 of the LAA cell. According to an embodiment, the firstbase station may transmit to a second wireless device, measurementconfiguration parameters determined based on the one or moreconfiguration parameters of frame structure Type 3 of the LAA cell.According to an embodiment, the first base station may configure cellconfiguration parameters of an LAA cell of the first base station basedon the one or more configuration parameters of frame structure Type 3 ofthe LAA cell. According to an embodiment, the second base station maytransmit to a third wireless device, one or more elements of the one ormore configuration parameters of frame structure Type 3 of the LAA cell.The second base station may transmit through the first cell, transportblocks based on the one or more elements of the one or moreconfiguration parameters of frame structure Type 3 of the LAA cell.According to an embodiment, the first base station may receive the cellconfiguration parameters from the second base station via a core networkentity.

FIG. 16 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 1610, a first base station transmits to asecond base station, cell configuration parameters of one or more cellsof the first base station. The cell configuration parameters comprise:at least one first information element (IE) indicating a firstidentifier of a first cell of the one or more cells; at least one secondIE indicating that the first cell is a licensed assisted access (LAA)cell; and at least one third IE indicating one or more configurationparameters of frame structure Type 3 of the LAA cell. At 1620, the firstbase station receives from the second base station, a handover requestmessage for a first wireless device. The handover request message isconfigured based on the one or more configuration parameters of framestructure Type 3 of the LAA cell.

According to an embodiment, the cell configuration parameters mayfurther comprise at least one of: at least one fourth IE indicating adownlink frequency; at least one fifth IE indicating an uplinkfrequency; at least one sixth IE indicating a downlink bandwidth; atleast one seventh IE indicating an uplink frequency, a combinationthereof, and/or the like. According to an embodiment, the one or moreconfiguration parameters of frame structure Type 3 of the LAA cell mayindicate at least one of: an LAA cell subframe configuration; a subframestart position; a cross carrier scheduling configuration unlicensed/LAAuplink; a listen-before-talk (LBT) configuration parameter comprising atleast one of a maximum energy detection threshold or an energy detectionthreshold offset; a physical downlink control channel (PDCCH)configuration unlicensed/LAA; a sounding reference signal uplinkconfiguration dedicated aperiodic; an LBT procedure category comprisingat least one of category 2, category 3, or category 4; a size ofcontention window for LBT procedure; a hybrid automated repeat request(HARQ) process number; a maximum number of scheduled subframes; amulti-antenna port transmission mode; a flexible timing supportindication between uplink grant and uplink transmission, a combinationthereof, and/or the like. According to an embodiment, the second basestation may configure one or more mobility parameters towards a cell ofthe first base station based on the one or more configuration parametersof frame structure Type 3 of the LAA cell.

In this disclosure, “a” and “an” and similar phrases are to beinterpreted as “at least one” and “one or more.” Similarly, any termthat ends with the suffix “(s)” is to be interpreted as “at least one”and “one or more.” In this disclosure, the term “may” is to beinterpreted as “may, for example.” In other words, the term “may” isindicative that the phrase following the term “may” is an example of oneof a multitude of suitable possibilities that may, or may not, beemployed to one or more of the various embodiments. If A and B are setsand every element of A is also an element of B, A is called a subset ofB. In this specification, only non-empty sets and subsets areconsidered. For example, possible subsets of B={cell1, cell2} are:{cell1}, {cell2}, and {cell1, cell2}. The phrase “based on” isindicative that the phrase following the term “based on” is an exampleof one of a multitude of suitable possibilities that may, or may not, beemployed to one or more of the various embodiments. The phrase “inresponse to” is indicative that the phrase following the phrase “inresponse to” is an example of one of a multitude of suitablepossibilities that may, or may not, be employed to one or more of thevarious embodiments.

In this disclosure, various embodiments are disclosed. Limitations,features, and/or elements from the disclosed example embodiments may becombined to create further embodiments within the scope of thedisclosure.

In this disclosure, parameters (Information elements: IEs) may compriseone or more objects, and each of those objects may comprise one or moreother objects. For example, if parameter (IE) N comprises parameter (IE)M, and parameter (IE) M comprises parameter (IE) K, and parameter (IE) Kcomprises parameter (information element) J, then, for example, Ncomprises K, and N comprises J. In an example embodiment, when one ormore messages comprise a plurality of parameters, it implies that aparameter in the plurality of parameters is in at least one of the oneor more messages, but does not have to be in each of the one or moremessages.

Furthermore, many features presented above are described as beingoptional through the use of “may” or the use of parentheses. For thesake of brevity and legibility, the present disclosure does notexplicitly recite each and every permutation that may be obtained bychoosing from the set of optional features. However, the presentdisclosure is to be interpreted as explicitly disclosing all suchpermutations. For example, a system described as having three optionalfeatures may be embodied in seven different ways, namely with just oneof the three possible features, with any two of the three possiblefeatures or with all three of the three possible features.

Many of the elements described in the disclosed embodiments may beimplemented as modules. A module is defined here as an isolatableelement that performs a defined function and has a defined interface toother elements. The modules described in this disclosure may beimplemented in hardware, software in combination with hardware,firmware, wetware (i.e. hardware with a biological element) or acombination thereof, all of which are behaviorally equivalent. Forexample, modules may be implemented as a software routine written in acomputer language configured to be executed by a hardware machine (suchas C, C++, Fortran, Java, Basic, Matlab or the like) or amodeling/simulation program such as Simulink, Stateflow, GNU Octave, orLabVIEWMathScript. Additionally, it may be possible to implement modulesusing physical hardware that incorporates discrete or programmableanalog, digital and/or quantum hardware. Examples of programmablehardware comprise: computers, microcontrollers, microprocessors,application-specific integrated circuits (ASICs); field programmablegate arrays (FPGAs); and complex programmable logic devices (CPLDs).Computers, microcontrollers and microprocessors are programmed usinglanguages such as assembly, C, C++ or the like. FPGAs, ASICs and CPLDsare often programmed using hardware description languages (HDL) such asVHSIC hardware description language (VHDL) or Verilog that configureconnections between internal hardware modules with lesser functionalityon a programmable device. Finally, it needs to be emphasized that theabove mentioned technologies are often used in combination to achievethe result of a functional module.

The disclosure of this patent document incorporates material which issubject to copyright protection. The copyright owner has no objection tothe facsimile reproduction by anyone of the patent document or thepatent disclosure, as it appears in the Patent and Trademark Officepatent file or records, for the limited purposes required by law, butotherwise reserves all copyright rights whatsoever.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example, and notlimitation. It will be apparent to persons skilled in the relevantart(s) that various changes in form and detail can be made thereinwithout departing from the scope. In fact, after reading the abovedescription, it will be apparent to one skilled in the relevant art(s)how to implement alternative embodiments. Thus, the present embodimentsshould not be limited by any of the above described exemplaryembodiments.

In addition, it should be understood that any figures which highlightthe functionality and advantages, are presented for example purposesonly. The disclosed architecture is sufficiently flexible andconfigurable, such that it may be utilized in ways other than thatshown. For example, the actions listed in any flowchart may bere-ordered or only optionally used in some embodiments.

Further, the purpose of the Abstract of the Disclosure is to enable theU.S. Patent and Trademark Office and the public generally, andespecially the scientists, engineers and practitioners in the art whoare not familiar with patent or legal terms or phraseology, to determinequickly from a cursory inspection the nature and essence of thetechnical disclosure of the application. The Abstract of the Disclosureis not intended to be limiting as to the scope in any way.

Finally, it is the applicant's intent that only claims that include theexpress language “means for” or “step for” be interpreted under 35U.S.C. 112. Claims that do not expressly include the phrase “means for”or “step for” are not to be interpreted under 35 U.S.C. 112.

What is claimed is:
 1. A method comprising: receiving, by a first basestation from a second base station, cell configuration parameters of oneor more cells of the second base station, the cell configurationparameters indicating: at least one first information element (IE)indicating a first identifier of a first cell of the one or more cells;at least one second IE indicating that the first cell is an unlicensedcell; and at least one third IE indicating radio frequency channelnumber of the unlicensed cell; and sending, to the second base station,a handover request message for a wireless device after receiving thecell configuration parameters.
 2. The method of claim 1, wherein thecell configuration parameters further indicate at least one of: adownlink frequency; an uplink frequency; a downlink bandwidth; or anuplink bandwidth.
 3. The method of claim 1, wherein the cellconfiguration parameters further indicate at least one of: an unlicensedcell subframe configuration; a subframe start position; a cross carrierscheduling configuration of an unlicensed uplink; a physical downlinkcontrol channel (PDCCH) configuration; a sounding reference signaluplink configuration dedicated aperiodic; a hybrid automated repeatrequest (HARD) process number; a maximum number of scheduled subframes;a multi-antenna port transmission mode; or a flexible timing supportindication between uplink grant and uplink transmission.
 4. The methodof claim 1, wherein the cell configuration parameters further indicateat least one of: a listen-before-talk (LBT) configuration parametercomprising at least one of: a maximum energy detection threshold; or anenergy detection threshold offset; an LBT procedure category comprisingat least one of category 2, category 3, or category 4; or a size ofcontention window for an LBT procedure.
 5. The method of claim 1,further comprising configuring, by the first base station, one or moremobility parameters towards a cell of the second base station based onthe cell configuration parameters.
 6. The method of claim 1, furthercomprising transmitting, by the first base station to a second wirelessdevice, measurement configuration parameters determined based on thecell configuration parameters.
 7. The method of claim 1, furthercomprising configuring, by the first base station, second cellconfiguration parameters of a second unlicensed cell of the first basestation based on the cell configuration parameters.
 8. The method ofclaim 1, wherein the first base station receives the cell configurationparameters from the second base station via a core network entity. 9.The method of claim 1, further comprising transmitting, by the secondbase station to a second wireless device, one or more parameters of thecell configuration parameters.
 10. The method of claim 9, furthercomprising transmitting, by the second base station via the unlicensedcell, transport blocks based the cell configuration parameters.
 11. Afirst base station comprising: one or more processors; and memorystoring instructions that, when executed by the one or more processors,cause the first base station to: receive, from a second base station,cell configuration parameters of one or more cells of the second basestation, the cell configuration parameters indicating: at least onefirst information element (IE) indicating a first identifier of a firstcell of the one or more cells; at least one second IE indicating thatthe first cell is an unlicensed cell; and at least one third IEindicating radio frequency channel number of the unlicensed cell; andsend, to the second base station, a handover request message for awireless device after receiving the cell configuration parameters. 12.The first base station of claim 11, wherein the cell configurationparameters further indicate at least one of: a downlink frequency; anuplink frequency; a downlink bandwidth; or an uplink bandwidth.
 13. Thefirst base station of claim 11, wherein the cell configurationparameters further indicate at least one of: an unlicensed cell subframeconfiguration; a subframe start position; a cross carrier schedulingconfiguration of an unlicensed uplink; a physical downlink controlchannel (PDCCH) configuration; a sounding reference signal uplinkconfiguration dedicated aperiodic; a hybrid automated repeat request(HARD) process number; a maximum number of scheduled subframes; amulti-antenna port transmission mode; or a flexible timing supportindication between uplink grant and uplink transmission.
 14. The firstbase station of claim 11, wherein the cell configuration parametersfurther indicate at least one of: a listen-before-talk (LBT)configuration parameter comprising at least one of: a maximum energydetection threshold; or an energy detection threshold offset; an LBTprocedure category comprising at least one of category 2, category 3, orcategory 4; or a size of contention window for an LBT procedure.
 15. Thefirst base station of claim 11, wherein the instructions, when executed,further cause the first base station to configure, by the first basestation, one or more mobility parameters towards a cell of the secondbase station based on the cell configuration parameters.
 16. The firstbase station of claim 11, wherein the instructions, when executed,further cause the first base station to transmit, by the first basestation to a second wireless device, measurement configurationparameters determined based the cell configuration parameters.
 17. Thefirst base station of claim 11, wherein the instructions, when executed,further cause the first base station to configure, by the first basestation, second cell configuration parameters of a second unlicensedcell of the first base station based on the cell configurationparameters.
 18. The first base station of claim 11, wherein the firstbase station receives the cell configuration parameters from the secondbase station via a core network entity.
 19. The first base station ofclaim 11, wherein the instructions, when executed, further cause thefirst base station to transmit, by the second base station to a thirdwireless device, one or more parameters of the cell configurationparameters.
 20. A system comprising: a first base station comprising:one or more first processors; and first memory storing firstinstructions that, when executed by the one or more first processors,cause the first base station to send cell configuration parameters ofone or more cells of the first base station, the cell configurationparameters indicating: at least one first information element (IE)indicating a first identifier of a first cell of the one or more cells;at least one second IE indicating that the first cell is an unlicensedcell; and at least one third IE indicating radio frequency channelnumber of the unlicensed cell; and a second base station comprising: oneor more second processors; and second memory storing instructions that,when executed by the one or more second processors, cause the secondbase station to: receive, from the first base station, the cellconfiguration parameters; and send, to the first base station, ahandover request message for a wireless device after receiving the cellconfiguration parameters.